EDITADO POR:

Agustin Cabral Prieto (ININ) Eduardo Carpiette (Direccin de Educacin Continua ya Distancia UAEM) Lorena Nara (IPN) Tobas Noel Nava (IMP) Oscar Olea (Facultad de Qumica-UAEM)

IMPRESO

Metepec, Estado de Mxico. Octubre 2014

DISEO: Direccin de Educacin Continua ya Distancia UAEM

ndicedetrabajos

LACAME2014.....................................................................................................................................................1Topics..................................................................................................................................................................2LatinAmericanConferenceontheApplicationofMssbauerSpectroscopy....................................................325AOSDECONGRESOSLATINOAMERICANOSDEESPECTROSCOPAMSSBAUER.................................5

Committees........................................................................................................................................................7Sponsors.............................................................................................................................................................8Thanks................................................................................................................................................................9SCIENTIFICPROGRAM......................................................................................................................................10InvitedSpeakers...............................................................................................................................................11T02:CONTRIBUTIONSOFMSSBAUERSPECTROMETRYTOTHESTUDYOFSOMEOXIDEDILUTED

MAGNETICSEMICONDUCTORS:ACRITICALREVIEW..........................................................................12T05:CHEMISTRYANDENVIRONMENTALAPPLICATIONSOFHIGHVALENTIRONOXOSPECIES................13T05:DESIGNOFSELFANDMATRIXSUPPORTEDSYSTEMSOFIRONOXIDENANOPARTICLESFOR

CATALYTICAPPLICATIONS...................................................................................................................14Participations....................................................................................................................................................15T02:MSSBAUERSPECTROSCOPYASSOURCEOFCOMPLEMENTARYAPRIORIINFORMATIONTOSOLVE

CRYSTALSTRUCTURESFROMXRDPOWDERDATA.............................................................................18T02:NUMERICALANALYSISOFBROADMSSBAUERSPECTRABYUSINGSIMPLEDISTRIBUTION

FUNCTIONS..........................................................................................................................................19T02:STRUCTURALANDHYPERFINEPROPERTIESOFMDOPEDSNO2(M=TRANSITIONMETALORRARE

EARTHELEMENT)NANOPARTICLES.....................................................................................................20T04:SYNTHESISANDCHARACTERIZATIONOFMAGNETITENANOPARTICLESFUNCTIONALIZEDWITH

CARBOXYLANDAMINOACIDSFORBIOMEDICALANDENVIRONMENTALAPPLICATIONS.................23T05:PHOTOCATALYTICEFFECTANDMSSBAUERSTUDYOFIRONTITANIUMSILICATEGLASSPREPARED

BYSOLGELMETHOD...........................................................................................................................25T06:57FeMSSBAUERSTUDYOFZIRCONIACONTAININGIRONVANADATECLYSTALLIZEDGLASSWITH

HIGHELECTRICALCONDUCTIVITY.......................................................................................................27T08:CORRELATIONBETWEENMILLINGTIMEOFPOWDER,ANDTHETEMPERATUREOFSUBSTRATEON

THEPROPERTIESOFNdFeTHINFILMS................................................................................................30T08:INFe2MnGaCOMPOUNDDOFeANDMnORDERMAGNETICALLYATTHESAMETEMPERATURE?

DOTHEYCOUPLEPARALLELORANTIPARALLELATLOWTEMPERATURES?.......................................31

T08:MAGNETICPROPERTIESOFTWOCORE/SHELLNANOPARTICLESCOUPLEDVIADIPOLARINTERACTION.............................................................................................................................................................32

T08:MSSBAUERANDSTRUCTURALSTUDYOFALLOYSFe1XVXOBTAINEDBYMECHANICALALLOYING..33T08:MSSBAUERINVESTIGATIONSONTHEDESORBTIONOFHYDROGENANDHYDROXYLFROMTHE

IRONOXIDENANOPARTICLES..............................................................................................................34T08:MSSBAUERSTUDYOFALLOYSFe67.5Ni32.5,PREPAREDBYALLOYMECHANICAL................................35T08:SPINDYNAMICSINCOEXISTINGANTIFERROMAGNETICANDSPINGLASSSTATESOFMULTIFERROIC

LEADPEROVSKITES..............................................................................................................................36T08:STUDYOFSTRUCTURAL,OPTICALANDMAGNETICPROPERTIESOFFeDOPED,CoDOPED,ANDFeCo

CODOPEDZnO....................................................................................................................................37T08:SYNTHESISANDCHARACTERIZATIONOFNixCo1xFe2O4Nanoparticles................................................38T08:SYNTHESISOFSILVERCOATEDMAGNETITENANOCOMPOSITEFUNCTIONALIZEDBYAZADIRACTHA

INDICA..................................................................................................................................................39T10:MSSBAUERANDXRDCHARACTERIZATIONOFTHEPHASETRANSFORMATIONSINAFeMnAlCAS.

CASTALLOYDURINGTRIBOLOGYTEST................................................................................................42T10:STRUCTURALSTUDYONLi2Fe1xNixSiO4...............................................................................................43

Posters..............................................................................................................................................................44Authorsindex.................................................................................................................................................133

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LACAME2014

XIVthLatinAmericanConferenceontheApplicationsoftheMssbauerEffectLACAME2014

LACAMEs are special scientific events. They are regional meetings that aim at stimulating thedevelopment ofMssbauer Spectroscopy (MS) in Latin American countries, all of themwith unparallelcommonculturalroots,butmostofthemwith limitedresources.MS isaparticulartechniquesuitableforpromotingthescientificdevelopmentinthesesocieties.TheorganizationofaconferencelikeLACAMEgivestheyoungscientistsoftheregionwhodonothavemanychancestovisitother laboratoriesorattendtheICAME meetings the opportunity to improve their scientific progress, and brings to the scientificcommunitiesandyoung researchers the feelingofhowexperimentalphysicscanbeperformedatahighlevel.

Asa consequenceof thesemeetings, theMssbauer community isgrowing in LatinAmerica.Newlaboratories have been set up and the improvement of the existing ones has been observed. Thecollaboration, interchangeandscientificagreementsbetween laboratories,someofthem isolatedpriortotheLACAMEconferences,havebeengreatlyenhanced.

TheXIVthLatinAmericanConferenceontheApplicationsoftheMssbauerEffectLACAME2014willbeheldfromNovember10thto14th,2014 inMexico.LACAMEstarted in1988 inRiode Janeiroandhasgrown steadily since then,changing thevenueevery twoyears fromdifferentnationswhereMssbauerresearchlaboratoriesexist.

Wedobelieve that the special ingredientaddedby LACAMEwillhelp flourish thedevelopmentofscienceandMSinthispartoftheworld;letushopethistrendcontinuesgrowing.

WewelcomeyoualltoLACAME2014.

November2014.

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Topics

T01AdvancesinexperimentationandDataProcessing

T02Amorphous,NanocrystalsandNanoparticles

T03ApplicationsinSoils,Mineralogy,Geology,CementsandArchaeology

T04BiologicalandMedicalApplications

T05Catalysis,CorrosionandEnvironment

T06ChemicalApplications,StructureandBonding

T07IndustrialApplications

T08MagnetismandMagneticMaterials

T09Multilayers,ThinFilmsandArtificiallyStructuredMaterials

T10PhysicalMetallurgyandMaterialsScience

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LatinAmericanConferenceontheApplicationofMssbauerSpectroscopyElisaBaggioSaitovitch

WecannotspeakaboutMssbauerspectroscopy inLatinAmericawithoutspeakingabout JacquesDanonwhopassedawayin1989.Hehasinitiatetoworkalreadyin1960inthisfieldatBrazilianCenterforResearch in Physics (CBPF), in Rio de Janeiro.He always insisted thatwe should not competewith thecountriesofnorthhemispherebutexerciseourcreativity in scientific research, looking for topics relatedwithour regionorhavinganewapproach in frontier topics,addressing topics thatcanbestudied in theframeofthescientificandtechnologicdifficulties(notfacilities).Healwayssaid:Loquees importante,noson las tcnicas y computadores, son las ideas. Solamente la creatividad puede generar un verdaderoprogresotantoenlacienciacomoencualquiercampodelaactividadhumana.

In theearlydaysofMssbauerspectroscopy inLatinAmerica therewasmore interaction; thiswasnot the casewhen I started towork inMssbauer spectroscopy.Danonalwaysmentioned collaborationwithAugustoMorenoyMoreno,inMexico,CarlosAbeledoandAlbertFech.HepublishedthefirstlecturesinSpanishontheMssbauereffectgivenattheEscuelaLatinoAmericanadeFsicathatwasheldinMexico,in1968.

In1985,whileparticipatinginacommissiontodiscussthefutureofCLAF(LatinAmericanCenterforPhysics) Irealizedhowbad thescientificcollaborationamongLatinAmericangroupsdoingresearchwas;they tend togivepriority to the interactionwithgroups innorthhemisphere.Thecollaborationwithourneighbors in LatinAmericawouldnotoccur spontaneously, itwasnecessary tobeworkedoutbecause,morethantheproximity,theyhavecommonproblems.

WiththeseideasinmindIwenttoaBrazilianmeetinginMssbauerspectroscopy,whichwasthelastfroma seriesgoing throughall thegroups (seeH.Rechenberg report).Our ideawas tochangeabit thescope including all Brazilian groups working in Hyperfine Interaction. There I have made anotherproposition:openthemeetingtoalltheMssbauergroupsinLatinAmerica.ThispropositionwasacceptedandIsuggestedthattheChairpersonshouldbeJacquesDanon,knowingthatIshoulddotheheavywork.

InNovember1988weorganizedinRio,withthehelpofRosaScorzellithefirstLACAME;thenameofourmeetingwas inspired in the ICAME. At those dayswewere able to bring togethermore than 129participants!IbelievethatmostofthepeopleworkinginthisareacametoRio.

Itwasdifficulttocontactallthepeople,inthiscasethecontributionofDanon

4

was essential: he knew everybody. But there was no email, no telephone and the bestcommunicationwas by telegram and fax. For the first time I learned aboutRaiza fromHavana, Jaen inPanamaorAburtoinMexico.

The situation in Brazil in 1989 was very favorable for our purpose; the inistry of Science andTechnology had been just created. I was able to get support from several Brazilian institutions andfoundationsasCBPF,CNPq,CNEN,FINEP,CAPESandCLAF.ThetotalbudgetwasaboutUS$50000andtheinvitationincludedairticket,hotelandmeals.

Circaof10nonLatinAmericanscientistspecialistsindifferentfieldswereinvitedandcontributedtothe successof the conference. I still rememberhow theeyesof some studentswere shiningwhen theycouldlistentotheseknownspecialistsinMssbauerspectroscopy.Alltheeffortwasworthwhile!

After thatwehad thenicemeeting inCubawith theconversationwithFidelCastroandmanynonLatinAmericanparticipants.Argentina,Chile,Peru,Colombia,Venezuela,PanamaandMexico(in2004), ithasbeenalongway,withalotofefforts(thechairpersonsknowitwell),buttheresultisexcellent.

Thenumberofparticipantshasdecreasedalongthese15years.Maybethere isnow lesspeople inthe fieldor less fundsavailable, thiswe stillneed to findout. InBrazil the stronggroupofPortoAlegre,where Iwas introduced toMssbauer spectroscopy, has only aminor activity and sometimes does notparticipate even in theBrazilianmeetings. To compensate nowwe have the group ofVitoria andOuroPreto,whichareveryactiveandhaveorganizedthelastBrazilianmeetings.NewgroupshavebeencreatedinPeru(VictorPeaRodrigues)andColombia(PerezAlcazar)andtheyareveryactiveaswecouldseeinthelast conferences. From the successivemeetingswe can follow the development of some students likeRestrepofromColombia.HegaveatalkinCaracasasaseniorscientist!

Despitethisconferencebecamesmallertheyareverydynamicwithalotofdiscussionandinterestingquestions.IhopewecankeepthisatmosphereforMexico.

Thismeetinghavebeen very important for theparticipants, researchersand students thatdonothavetheopportunitytoparticipateintheICAMEs.TraditionallysomefewnonLatinAmericanspecialistsareinvitedspeakerstogetherwithlocalresearchersfromareaswhereMssbauerspectroscopycanbeapplied.Forexample, inVenezuelawehadsometalkaboutPetroleum industry.Wetrytoavoid invitingthesamenonLatinaAmericanspecialistsintwosuccessivemeetingsinordertocoverdifferentareas.

The LACAME has contributed for the collaboration among LA groups and for spreading thisspectroscopy in LA. All the applications are being studied, including minerals, meteorites, soils,superconductingandmagneticmaterials,milling,catalyses,corrosion,chemistry,thinfilms,heavyfermions,

5

etc. Howeverwe still hope to be able to improve the shearing of the facilities among the groups andestablishbilateralofficialexchangeprograms.

OnaregularbasistheLACAMEconferencesareorganized inLatinAmerica,eachtwoyearsandwesucceeded in organizing and reinforcing the collaboration among the Mssbauer community in LatinAmerica.ExceptfortheconferenceinChiletheProceedingshavebeenpublishedbyHyperfineInteraction.25AOSDECONGRESOSLATINOAMERICANOSDEESPECTROSCOPAMSSBAUER

Por estos das se estn cumpliendo los 25 aos de nuestra existencia como comunidad

latinoamericana de espectroscopa Mssbauer. Es con enorme alegra que queremos celebrar esteaniversario.

En 1988, con la excepcin de Brasil, que realizaba desde1982 encuentros locales de jvenesinvestigadores, en nuestro continente haba algunos laboratorios dispersos con investigadores quepretendamoshacerbuenacienciasinmuchosmediosapesar lasgrandesdificultadesquesepresentabanennuestrospases.Esto cambiarapara siempre cuando,entreel31deoctubreyel4denoviembrede1988seorganizelprimerCongresoLatinoamericanodeEspectroscopaMssbauer.Allnosconocimosyrpidamentenosidentificamoscomoformandopartedeunacomunidadcientfica.

Enestosveinticincoaos,hemos crecido individualy colectivamenteynos sentimosmiembrosdeuna realidad que trasciende las fronteras de nuestros pases para constituirse en una unidadlatinoamericanaqueencuentragranplaceryventajaencolaborarconcolegasdeotrospasesdelareginyreencontrarse con viejos (y no tan viejos) amigos cada dos aos en los LACAME y en numerosascolaboracionesentredistintosmiembrosdelacomunidad.

En este tiempo hemos visto aparecer laboratorios de luz sincrotrn, centros de microscopaelectrnica, la Internet. Ennuestraspropias instituciones sehan agregado nuevas tcnicasque como lacalorimetraolamagnetometranoshanpermitidoprofundizarenormementenuestrasinvestigaciones.Sinembargo, todo esto no ha desviado nuestra conviccin de que lo que nos une es la espectroscopaMssbauer.

Enotroscontinentesestarealidadesdemuchamenor intensidadosimplementenoexisteya.PerociertamenteenAmricalatinanuestroscongresosgozandeprestigioydeentusiasmo,connuevosjvenesquesesientenpartedeestacomunidadconvocantequetieneungranreconocimientointernacional.

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Poreso,elComitLatinoamericanodeEspectroscopaMssbauersaludajubilosamentealoscolegaslatinoamericanosyhacevotosparaquelasnuevasgeneracionestenganxitoensusesfuerzosdecontinuarymejorarloqueyahasidohechohastaaqu.

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CommitteesIntenationalCommitteeE.M.BaggioSaitovitch CBPFBrazilN.R.FuretBridn CNICCubaF.GonzlezJimnez UCVVenezuelaJ.A.Jan UPPanamR.C.Mercader UNLPArgentinaN.Nava IMPMxicoV.A.PeaRodrguez UNMSMPerG.A.PrezAlczar UVColombiaCarmenPizarro USACHChileLocalorganizingcommitteeHumbertoArriolaS. FacultaddeQumica,UniversidadNacionalAutnomadeMxicoAgustnCabralPrieto InstitutoNacionaldeInvestigacionesNuclearesNariaAdrianaFloresFuentes EscuelaSuperiorFsicoMatemticas,InstitutoPolitcnicoNacionalArturoGarcaBorquez EscuelaSuperiorFsicoMatemticas,InstitutoPolitcnicoNacionalEduardoGmezGarduo DECyD,UniversidadAutnomaEstadoMxicoEzequielJaimesFigueroa DECyD,UniversidadAutnomaEstadoMxicoRafaelLpezCastaares FacultaddeQumica,UniversidadAutnomaEstadoMxicoFabiolaMonroyGuzmn InstitutoNacionaldeInvestigacionesNuclearesNoelNavaE. InstitutoMexicanodelPetrleoOscarOleaCardoso FacultaddeQumica,UniversidadAutnomaEstadoMxicoOscarF.OleaMejia FacultaddeQumica,UniversidadAutnomaEstadoMxicoJessSobernM. Investigador

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Sponsors

AbdusSalamInternationalCentreforTheoreticalPhysics

SociedadQumicadeMxico

UniversidadAutnomadelEstadodeMxico

ConsejoMexiquensedeCienciayTecnologa

InstitutoNacionaldeInvestigacionesNucleares

InstitutoMexicanodelPetrleo

9

Thanks

LosComits InternacionalyLocalde laXIVLatinAmericanConferenceontheApplicationsoftheMssbauerEffectaprecianyagradecenprofundamentealRectordelaUniversidadAutnomadelEstadodeMxico,Dr.enD.JorgeOlveraGarca,porhabernospermitidorealizarestaconferenciaenlasinstalacionesdelaDireccindeEducacinContinuayaDistancia(DECyDUAEM).Asmismo,agradecemos alMaestroEzequiel Jaimes Figueroa,Directorde laDECyDUAEM,portodoelapoyoyfacilidadesquenosbrinddurantelaorganizacindedichaconferencia,ascomoasuequipodetrabajoporsuinvaluableaportacinparaprepararelcompendiodelosresmenesquesepresentanenestelibro.

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SCIENTIFICPROGRAM

SUNDAYNOV.9

MONDAYNOV.10

TUESDAYNOV.11

WEDNESDAYNOV.12

THURSDAYNOV.13

FRIDAYNOV.14

9:00OpeningCeremony

9:00JAJaen

9:00MiraRisticVideoC

9:00ElisaBaggioSaitovitch

9:00RobertoC.Mercader

9:30CesarABarreroM

9:45Coffee

9:45Coffee

9:45Coffee

10:15Coffee

10:05VSharma

10:00Coffee

10:05F.J.Litterst

10:05EdilsoReguera

10:35EdsonP

10:50W.T.Herrera Citytour

10:50P.M.A.Caetano11:10DagobertoOyolaLozano11:30HerojitSingh11:50J.J.Beltrn12:10J.L.Lpez

10:50ConcludingRemarks

11:20G.A.PrezAlczar

11:30S.Kubuki

11:40JosDomingosFabris

11:50AguirreContreras

NextLACAME

12:00Y.Takahashi,

12:10BentezRodrguez

12:20Lunch

12:30Lunch

12:30Lunch

14:00RojasMartnez

14:00POSTERSESSION1

14:00POSTERSESSION2

14:20J.A.H.Coaquira

18:00Registration

LatinAmericanRoundTable

19:0021:00Welcome

11

InvitedSpeakers

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T02: CONTRIBUTIONS OF MSSBAUER SPECTROMETRY TO THE STUDY OF SOME OXIDE DILUTED MAGNETIC SEMICONDUCTORS: A CRITICAL REVIEW J.J. Beltrn1, A. Punnoose2, K. Nomura3, E.M. Baggio-Saitovitch4, and C.A. Barrero1

1Grupo de Estado Slido, Facultad de Ciencias, Universidad de Antioquia, Medelln, Colombia.

2Department of Physics, Boise State University, Boise, USA 3Department of Applied Chemistry, School of Engineering, The Tokyo University, Tokyo, Japan

4Centro Brasileiro de Pesquisas Fsicas, Rio de Janeiro, Brazil. *Corresponding author: e-mail: cesar.barrero@udea.edu.co Keywords: Fe doped ZnO, Fe doped SnO2, nanoparticles. Topic: T02- Amorphous, Nanocrystals and Nanoparticles In 2005, the prestigious journal Science [1] posed a list of 125 unsolved scientific questions, one of them being: is it possible to create magnetic semiconductors that work at room temperature?. In 2008, Coey et al. [2] mentioned that the origin of the magnetism in Diluted Magnetic Semiconductors (DMS) is one of the most puzzling investigations. And to date we can say that the understanding of such phenomena is still a great challenge in materials science. In fact, there is no agreement between the various theoretical and experimental studies performed on the origin of the ferromagnetic signal in DMS, particularly in Oxide-DMS (ODMS). From the experimental side, the use of different characterization techniques, including Mssbauer spectrometry (MS), is an important requirement to achieve a better understanding of the phenomena. In this presentation we will show some examples of the contributions that 119Sn and 57Fe MS have done to the characterization of Fe-doped ZnO [3], Fe-Co codoped ZnO [4], Fe-doped SnO2 [5-7] and Fe-Sb codoped SnO2 [8,9] nanoparticles. We will show how this technique has contributed to the: (i) demonstration of the absence of both spurious phases and clustering of dopants, (ii) determination of the preferable sites, high or low spin character, and oxidation states of the transition metal (TM) ions, (iii) identification of the preferable location of the TM ions, either at the surface, at the interior or in the whole nanoparticles, (iv) identification and

characterization of defects, (v) proper characterization of the electronic, crystallographic, and magnetic properties, and their possible relations, (vi) and determination of the TM ions that are involved in the magnetic ordering. References [1] Kennedy and Norman, Science 309 (2005) 82. [2] J.M.D. Coey, K. Wongsaprom, J. Alaria, and M. Venkatesan, J. Phys. D.: Appl. Phys. 41 (2008) 134012. [3] J.J. Beltrn, J.A. Osorio, C.A. Barrero, C.B. Hanna and A. Punnoose, J. Appl. Phys. 113 (2013) 17C308. [4] J.J. Beltrn, C.A. Barrero, A. Punnoose, J. Phys. Chem. C, V. 19 (3) (2014) [5] A. Punnoose, K. Dodge, J.J. Beltrn, K.M. Reddy, N. Franco, J. Chess, J. Eixenberger, and C.A. Barrero, J. Appl. Phys. 115 (2014) 17B534 [6] J.J. Beltrn, L.C. Snchez, J. Osorio, L. Tirado, E.M. Baggio-Saitovitch, and C.A. Barrero, J. Mater. Sci. 45 (2010) 5002 [7] K. Nomura, C.A. Barrero, J. Sakuma, and M. Takeda, Phys. Rev. B 75 (2007) 184411 [8] K. Nomura, C.A. Barrero, K. Kuwano, Y. Yamada, T. Saito, E. Kuzmann, Hyperfine Interact. 191 (2009) 25. [9] K. Nomura, E. Kuzmann, C.A. Barrero, S. Stichleutner, and Z. Homonnay, Hyperfine Interact. 184 (2008) 57.

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T05: CHEMISTRY AND ENVIRONMENTAL APPLICATIONS OF HIGH-VALENT IRON-OXO SPECIES

Virender K. Sharma1*, Radek Zboril2, Libor Machala2, and Karolina Siskova2 1Departent of Environmental and Occupational Health, School of Public Helath, Texas A&M University 1266 TAMU, SPH

101, College Station, Texas. 2 Regional Centre of Advanced Technologies and Materials, Departments of Experimental Physics and Physical

Chemistry, Faculty of Science, Palacky University, 78371 Olomouc, Czech Republic *Corresponding author: e-mail: vsharma@sph.tamhsc.edu Keywords: Ferrate, oxidation, decontamination Topic: T05- Catalysis, Corrosion and Environment The chemistry of iron has been developed early in the history of mankind as it is the basic metal of the industrial society and its ore is profoundly present globally. Iron as the most abundant transition element, present in alloy with nickel, and constitutes about a third of entire mass of the Earth crust. Iron is important for most of the living organisms. Iron has a unique range of valence states from zero to +6 oxidation states, which have numerous applications in medicine, energy, nanotechnology, biocatalysis, energy, and environmental remediation. Examples of biocatalysis include involvement of high-valent oxoiron(IV) (FeIV = O) and oxoiron(V) (FeV = O) species in a number of enzymatic systems (1). These high-valent iron species participate in halogenation, epoxidation, and hydroxylation reactions. In the last decade, our research group is researching the simple oxo-compounds of higher-valent iron species, commonly called ferrates (FeVIO42-, Fe(VI), FeVO43-, Fe(V), and FeIVO44-, Fe(IV)) in aqueous solution, which have shown their applications in energy materials, green organic synthesis, and waste remediation (2). Examples of remediation are oxidative transformations of toxic inorganic and organic contamination to non-toxic by products, inactivation of virus and bacteria, and removal of toxic metals (e.g. arsenic) (3, 4). The focus of the presentation will be on demonstrating the chemistry and applications of these high-valent iron species in water treatment technology. Mssbauer spectra of Fe(VI), Fe(V), Fe(IV) and Fe(III) species can be used to distinguish these iron species in the solid phase and in the solution

mixture. The isomer shift values of ferrates decreased almost linearly and can be expressed as (mm s-1) = 1.084 0.326 OS (1) Mechanisms of the reactions of ferrates with different contaminants were studied using Mssbauer spectroscopy in conjunction with other spectroscopic and surface techniques. Figure 1 shows the example of studying the removal of arsenic by Fe(VI) in which ex-situ and in-situ removal by Fe(III), generated from Fe(VI), differ.

Figure 1. Different mechanisms of arsenic removal by Fe(III), ex-situ sorption (left) and Fe(VI) induced in-situ structural incorporation (right) (5). References [1] J. Hohenberger, K. Ray, and K. Meyer, Nature Commun. 3720 (2012). [2] V. K. Sharma, Coord. Chem. Rev. 257 (2013) 494-510. [3] E. Casbeer, V.K. Sharma, Z. Zajickova, and D.D. Dionysiou, Environ. Sci. Technol., 47 (2013), 4572-4580. [4] V.K. Sharma, J. Environ. Manage. 92 (2011), 1051-1073. [5] R. Prucek, J. Tucek, J. Kolak, J. Filip, Z. Maruk, V.K. Sharma, and R. Zboril, Environ. Sci. Technol. 47 (2013) 3283-3292.

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T05: DESIGN OF SELF AND MATRIX-SUPPORTED SYSTEMS OF IRON OXIDE NANOPARTICLES FOR CATALYTIC APPLICATIONS I.O. Prez de Berti1, J.F. Bengoa1, S.G. Marchetti1, R.C. Mercader2*

1CINDECA, CONICET, CICPBA, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 N 257, 1900 La

Plata, Argentina 2 Instituto de Fsica La Plata, CCT-CONICET, Departamento de Fsica, Facultad de Ciencias Exactas, Universidad

Nacional de La Plata, 115 y 49, 1900 La Plata, Argentina *Corresponding author: e-mail: mercader@fisica.unlp.edu.ar Keywords: Fischer-Tropsch reaction, semi-model catalysts, Mssbauer characterization, pre-synthesized nanoparticles Topic: T05- Catalysis, Corrosion and Environment Metallic nanoparticles are widely used as supported catalysts in many industrial chemical reactions. A detailed understanding of the enhancement that the nanoparticles bring about in the stability, activity, and selectivity of the solids requires quasi-model catalysts with well-defined surfaces and supported nanoparticles of homogeneous size. The usual way of synthesizing catalysts of supported nanoparticles is to impregnate the solid with a solution that contains the metal salts that will give rise to the catalyst. However, this route doesn't necessarily lead to a catalyst close to the ideal conditions. The Fischer-Tropsch synthesis is a reaction in which a mixture of hydrogen and carbon monoxide converts into liquid hydrocarbons mediated by the presence of a catalyst. The reaction process can be written as: nCO + (2n+1) H2 CnH2n+2 + nH2O In spite that it was developed in the 1920s and that it has been intensively used over many decades, the intrinsic mechanism of how it proceeds is not fully known. In particular, the activity and selectivity depend on factors that are not easy to isolate. One of them is the so-called structure sensitivity. To be able to study the diverse influence of the different parameters in the activity and selectivity of the catalysts, we set about to prepare quasi-model catalysts by a route different from the usual one; we pre-synthesized systems of narrowly size-distributed nanoparticles and introduced them afterwards into the already synthesized matrix. In this talk we will describe the results obtained after the preparation of Fischer-Tropsch catalysts made up 3 nm maghemite nanoparticles supported on SBA-15 matrices. The catalysts were prepared by pre-synthesizing -Fe2O3 particles and further embedding them into a modified SBA-15 matrix. The results showed that the solid kept its structural properties over impregnation, activation and catalytic reaction performed in realistic

conditions. Out of the many techniques by which we characterized the solids, Mssbauer spectroscopy was the one that yielded the more helpful results allowing the identification of all the relevant intervening iron species.

Figure 1. Mssbauer spectra of -Fe2O3/SBA-15 catalysts measured at the temperatures indicated after a catalyst reaction conducted at 20 atm. As an example of the results that will be considered in the talk, Fig. 1 displays the Mssbauer spectra of two catalysts that produced a high activity and a good olefin/paraffin ratio over the Fischer-Tropsch reaction at 20 atm after being activated in a CO-H2:CO atmosphere (left) and H2 atmosphere (right). Both solids underwent catalysis tests and were measured in a specially designed cell that enabled keeping the same reactor atmosphere when taken over to the Mssbauer spectrometer.

15

Participations

16

T01AdvancesinexperimentationandDataProcessing

17

T02Amorphous,NanocrystalsandNanoparticles

18

T02: MSSBAUER SPECTROSCOPY AS SOURCE OF COMPLEMENTARY A PRIORI INFORMATION TO SOLVE CRYSTAL STRUCTURES FROM XRD POWDER DATA

Edilso Reguera Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute, Mexico, D. F., Mexico; Corresponding author: e-mail: edilso.reguera@gmail.com Topic: T02- Amorphous, Nanocrystals and Nanoparticles Mssbauer spectra provide information on the coordination geometry for the atom involved in the -resonant nuclear absorption, on the nature of first and second neighbors, and on its electronic structure and relative occupation of structural sites in the solid. All this information is relevant to solve the crystal structure of new materials from XRD powder data. To solve the crystal structure of a new material the best option is to have diffraction data from a single crystal. Such possibility is available only for a small fraction, usually < 10 %, of practical situations. In a single crystal experiment, the diffraction pattern is the Fourier Transform for the sample in the inverse space and the crystal model to be refined (in the direct space) is obtained from the Inverse Fourier Transform of the recorded diffraction pattern. In XRD powder experiment, the 3D structural information is

projected in 1D space. From this fact, the crystal structure for this kind of data must be solved through an ill-posed problem. This supposes the availability of a priori structural information or boundary conditions for the mathematical problem to be solved. Such a priori information is usually obtained from spectroscopic techniques. Nuclear, electronic and vibrational spectra contain information on the local symmetry (coordination geometry) and nature of the first neighbors for the atom(s) involved resonant absorption and re-emission. In this contribution, the scope of Mssbauer spectroscopy in that sense is discussed, from several illustrative examples, where the crystal structure was solved and then refined, using the corresponding Mssbauer spectra as source of the required a priori structural information.

19

T02: NUMERICAL ANALYSIS OF BROAD MSSBAUER SPECTRA BY USING SIMPLE DISTRIBUTION FUNCTIONS

B. Aguilar-Garca1, A. Sandoval-Nandho1, I. Garca-Sosa2 O. R. Lpez-Castaares3, O. Olea-Cardoso3 and A. Cabral-Prieto2(*)

1Universidad Autnoma Metropolitana-Cuajimalpa, Avenida Vasco de Quiroga 4871, Cuajimalpa, Santa Fe Cuajimalpa, 05300 Ciudad De Mxico, D.F. 2 Instituto Nacional de Investigaciones Nucleares, Departamento de Qumica, Apdo. Postal 18-1027, Col. Escandn, Deleg. M. Hidalgo, C. P. 11801, Mxico. D. F., Mxico. 3Universidad Autnoma del Estado de Mxico, Paseo Universidad #100, Universitaria, 50130 Toluca de Lerdo, Estado de Mxico *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: Broad Mssbauer spectra, hyperfine distributions, goettite Topic: T02- Amorphous, nanocrystal and nanoparticles The analysis of broad Mssbauer spectra is usually handled by using the convolution between the Gaussian and Lorentzian lines. There are, however, many cases were this convolution does not give meaningful results because the Mssbauer spectra are the result of a complex superposition of several patterns and the discrete hyperfine parameters are difficult to calculate from them. In such cases the use of hyperfine distribution functions are preferred [1]. In this paper simple distribution functions are used to analyze the Mssbauer spectrum of Goethite nanoparticles. The asymmetrical triangle is shown in Fig. 1.

Figure 1 (a) Mssbauer spectrum of goethite

nanoparticles recorded at 77K. (b) Asymmetrical triangular distribution function may be used to

properly fit this spectrum. Typical representations of the hyperfine field distributions (HFD) for this nano material are as shown in Fig. 2 (a) and (b), obtained with known methods [1, 2].

Figure 2. (a) Step distribution function [1], (b) Fourier

series expansion [2].

Figure 3. (a) Gaussian, (b, c) Rational, (d) binomial

distribution functions. Figure 3 shows, on the other hand, three atypical representations of the HFD. The decaying curve, after the maxima, does not appear which seems to be unnecessary for cases like this. If it does such a decay is abrupt as indicated in figs. 1 (a). Fig. 2 (a) and (b) or Fig. 3 (b). In all these cases there is always a question left: what of the seven HFDs, here presented, represents best the experimental data. Morup et al. [3] reproduces the asymmetry of a Mssbauer spectrum by using an asymmetrical distribution function for the crystal size of nanomaterials. Thus, Fig. 3 (d) may be the best searched solution instead of Fig. 2 (b). In all presented cases the same order of magnitude for squared Ji is, however, acceptable. References [1] J. Hesse, A. Rbartsch, Journal of Physics E 7 (1974) 526. [2] Window, B.: J. Phys. E: Sci. Intrum. 4, 401 (1971) [3] S. Mrup , H. Topse and J. Lipka, Journal de Physique Colloque C6, sup.12, Tome 37, (1976) C6-287.

T02: STRUCTURAL AND HYPERFINE PROPERTIES OF M-DOPED SNO2 (M=TRANSITION METAL OR RARE EARTH ELEMENT) NANOPARTICLES

J. A. H. Coaquira1, F. H. Aragn1, J. C. R. Aquino1, R.Cohen2, L.C.C.M. Nagamine2, P. Hidalgo3, D. Gouva4

1Instituto de Fsica, Universidade de Braslia, Ncleo de Fsica Aplicada, Braslia DF 70910-900, Brazil. 2 Instituto de Fsica, Universidade de So Paulo, SP 05508-090,Brazil

3Faculdade Gama-FGA, Sector Central Gama, Universidade de Braslia, Braslia, DF 72405-610, Brazil. 4Departamento de Metalurgia e Engenharia de Materiais, Escola Politcnica, Universidade de So Paulo, So Paulo SP

05508-900, Brazil. *Corresponding author: e-mail: coaquira.ja@gmail.com Keywords: M-doped SnO2 nanoparticles, Mssbauer spectroscopy, structural properties Topic: T02- Amorphous, Nanocrystals and Nanoparticles The possibility of using the magnetic properties of magnetic gas sensing materials instead of their conventional electrical properties is moving forward the interest for dilute magnetic semiconductor oxides. The SnO2 compound is a wide band-gap (~3.5 eV) semiconductor and widely used as a conventional gas sensor due to its high reactivity with environmental gases. The doping of this semiconductor using transition metals changes its sensitivity, selectivity and time response with respect to a number of pollutant gases. However, the use of magnetic gas sensors requires that the sensing material shows magnetic order above room temperature. Although reports indicate room temperature ferromagnetic properties of transition-metal-doped SnO2 thin films and powders, the origin of that order is not clear yet [1].

0 1 2 3 4 5 6 7

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Figure 1. Room-temperature Mossbauer spectra of Gd-doped SnO2 nanoparticles. Isomer shift (IS) as a function of the Gd content.

In this work, we report the study of the structural and magnetic properties of M-doped SnO2 (M=transition metal or rare earth element) nanoparticles synthesized by a polymer precursor method [2]. X-ray diffraction patterns indicate the formation of only the rutile phase for the whole set of samples. Undoped SnO2 nanoparticles show an average particles size of ~11 nm and this size shows a decreasing tendency as the M content is increased, regardless the M dopant. This crystalline size is further corroborated by TEM images. Magnetic measurements, carried out in a wide range of temperature and applied magnetic field, suggest the coexistence of ferromagnetic and paramagnetic phases. Depending on the dopant content, a ferromagnetic behavior which survives until high temperatures is determined. Mssbauer spectra, carried out using a Ca119mSnO3 radiation source, show no evidences of magnetic splitting and, depending on the doping element (M), room temperature Mssbauer spectra are well resolved by considering doublets. The origin of these doublets and the effects on the quadrupole splitting and isomer shift due to the doping are discussed in this work. References [1] W. Wang, Z. Wang, Y. Hong, J. Tang, and M. Yu, J. Appl. Phys. 99 (2006) 0M115. [2] D. Gouva, A. Smith, J. P. Bonnet, Eur. J. Solid State Inorg. Chem. 33 (1996) 1015.

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21

T03ApplicationsinSoils,Mineralogy,Geology,CementsandArchaeology

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T04BiologicalandMedicalApplications

23

T04: SYNTHESIS AND CHARACTERIZATION OF MAGNETITE NANOPARTICLES FUNCTIONALIZED WITH CARBOXYL AND AMINO ACIDS

FOR BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS W. T. Herrera1, A.G. Bustamante Domnguez1, M. Giffoni2, E. Baggio-Saitovitch2 and J. Litterst3

1 Ceramics and Nanomaterials Laboratory, Department of Physics, National University of San Marcos

(UNMSM), A.P. 14-0149, Lima 14, Per. 2 Brazilian Center for Physics Research (CBPF), 22290-180, Rio de Janeiro, Brazil.

3 Institute for Physics of Condensed Matter, Technische Universitt Braunschweig (TU Braunschweig), Mendelssohnstrasse 3, D-38106 Braunschweig, Germany.

*Corresponding author: e-mail: wiliam@agdes.pe Keywords: magnetite nanoparticles functionalized, magnetic nanoparticles Topic: T04 - Biological and Medical Applications This work involves the synthesis of magnetite nanoparticles (NPs) functionalized with lauric acid (LA), oleic acid (OA) and lysine (Lys). The synthesis was carried out using a chemical route of co-precipitation. This route allows the production of NPs functionalized using a basic infrastructure, low cost of production, the latter very important, especially if we consider the potential applications in the field of environmental remediation. In the case of biomedical applications also chemical route is the best alternative in this case however requires a more extensive characterization and clinical trials.

After synthesis of functionalized NPs these were characterized with the techniques: X-ray diffraction (XRD), transmission electron microscopy (TEM), Mssbauer spectroscopy (MS), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). Of the analysis made by the different techniques we concluded that functionalized NPs are of very good quality. All were magnetic with magnetic saturation of 60 emu/g, for the

case of NPs coated with AL. The XRD and TEM measurements show that the NPs have an average size between 9 and 11 nm with spinel crystal structure with lattice parameter of 8.37 . XPS measures determined that iron atoms has a valence of +3 and +2, with a total ratio of iron atoms Fe3+:Fe2+ of 2:1. Of the FTIR measurements we show that AL and AO molecules are chemically bound to the surface of the NPs. By TGA measures we calculate the number of functionalized molecules. In the case of NPs coated with AL and AO were 1974 and 1486, respectively.

References [1] Gupta, A.K., Gupta, M., Biomat. (2005) 26, 3995. [2] Kas, R., Sevinc, E., Topal, U., Acar, H.Y., J. Phys. Chem. (2010) 114, 7758. [3] Tsedev Ninjbadgar, et al, Solid State Sciences 6, (2004) 879885. [4] Katerina Kluchova et al. Biomaterials 30 (2009) 28552863.

24

T05Catalysis,CorrosionandEnvironment

25

Figure 1. XRD patterns of FSxTi with 'x' of (A) 10 and (B) 40 annealed at (a) 400 oC and (b) 1000 oC for 3h.

Figure 2. FeMS of FSxTi with 'x' of (A) 10 and (B) 40 annealed at (a) 400 oC and (b) 1000 oC for 3h.

T05: PHOTOCATALYTIC EFFECT AND MSSBAUER STUDY OF IRON

TITANIUM SILICATE GLASS PREPARED BY SOL-GEL METHOD Y. Takahashi1*, S. Kubuki1, K. Akiyama1, K. Sink 2 and T. Nishida3

1Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University,

Minami-Osawa 1-1, Hachi-Oji, Tokyo 192-0397, JAPAN 2Institute of Chemistry, Faculty of Science, Etvs Lornd University, Pzmny P.s. 1/A, Budapest 1117,

HUNGARY 3Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and

Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN *Corresponding author, e-mail: takahashi-yusuke3@ed.tmu.ac.jp Keywords: photocatalyst, silicate glass Topic: T05- Catalysis, Corrosion and Environment 1. Introduction Anatase type TiO2 is well known as a photocatalyst activated by the UV light [1]. It will be more effective to develop photocatalysts which show their activity under visible light irradiation. Recently, Takahashi et al. reported that 50Fe2O350SiO2 (in mass %) glass had photocatalytic activity under the visible light [2]. This result implies that iron silicate glass might be a practical photocatalyst with high efficiency. In this study, we report a relationship between local structure and visible light activated photocatalytic effect of iron titanium silicate glass prepared by sol-gel method. 2. Experimental Iron titanium silicate glasses with a composition of 50Fe2O3(50-x)SiO2xTiO2 (in mass %, x = 10-40, abbreviated as FSxTi) were prepared by sol-gel method. Reagent chemicals of Si(OC2H5)4, Fe(NO3)39H2O, Ti(OCH(CH3)2)4, HNO3, and C2H5OH were poured into a beaker and well mixed for 2 h at RT. After having been agitated by reflux-heat method at 80 oC for 2 h, the solution was poured into a glass vial and dried at 60 oC for 3 days to obtain dark brown gel samples. The samples were annealed between 400 and 1000 oC for 3 h in air. For the structural characterization, 57Fe-Mssbauer spectra (FeMS) were measured by a constant acceleration mode with a source of 57Co(Rh) with -Fe as a reference and X-ray diffractmetry (XRD) was carried out at 2 between 10 and 80 with an interval and scanning rate of 0.02 and 5 min-1, respectively. X-ray with the wavelength of 1.54 generated by Cu filament was targeted by electron accelerated by 300 mA and 50 kV. 3. Results and Discussion As shown in Figs. 1 (A-a) and (B-a), XRD patterns of FSxTi with x of 10 and 40 annealed at 400 oC showed halo patterns due to

amorphous structure, while intensive diffraction peaks attributed to crystalline phases of Fe2TiO5, -Fe2O3 and TiO2 were observed when annealed at 1000 oC (Figs. 1 (A-b) and (B-b)). FeMS of FS10Ti annealed at 1000 oC for 3 h showed a sextet with of 0.38 mm s-1, of -0.22 mm s-1and int of 50.6 T due to -Fe2O3 and a doublet with of 0.38 mm s-1 and of

0.76 mm s-1 due to Fe2TiO5 (Fig. 2 (A-b)). -Fe2O3 could not be detected from the XRD pattern and the FeMS of FS40Ti annealed at 1000 oC. These results indicate that the kinds and fraction of crystalline phases precipitated in FSxTi can be controlled by the annealing conditions and the chemical composition. The photocatalytic effect of FSxTi is presented on the day of the conference. References [1] A. Fujishima, K. Honda, Nature 238 (1972) 37-38. [2] Y. Takahashi, S. Kubuki, K. Akiyama, K. Sink, E. Kuzmann, Z. Homonnay, M. Risti, T. Nishida, Hyperfine. Interact. 226 (2014) 747-753

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T06ChemicalApplications,StructureandBonding

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T06: 57Fe-MSSBAUER STUDY OF ZIRCONIA CONTAINING IRON VANADATE CLYSTALLIZED GLASS WITH HIGH ELECTRICAL CONDUCTIVITY

K. Matsuda1, S. Kubuki1*, K. Akiyama1 and T. Nishida2

1 Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi-Oji, Tokyo 192-0397, JAPAN.

2 Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN.

*Corresponding author: e-mail: kubuki@tmu.ac.jp Keywords: vanadate glass, electron hopping, heat-treatment, monoclinic vanadium-zirconia, beta-vanadium bronzes Topic: T06- Chemical Applications, Structure and Bonding Introduction Vanadate glass is known as a semiconductor with the electrical conductivity () of 10-7-10-5 S cm-1 due to 3d electron (polaron) hopping from VVI (or VIII) to VV [1]. A drastic increase in of up to 100 Scm-1 was observed for barium iron vanadate glass, BaO-Fe2O3-V2O5 caused by heat treatment (HT), which has a registered trademark of NTAglassTM [2]. This unique electrical property shows that vanadate glass will be a good candidate for electrode of secondary batteries. In order to find a vanadate glass with higher , we have investigated several vanadate glasses. In the present study, we report a new conductive vanadate glass containing ZrO2 with high value without HT. Experimental A new vanadate glass with the composition of xZrO210Fe2O3(90x)V2O5 (x=0-30), abbreviated as xZFV, was prepared by a conventional melt-quenching method under the melting temperature and time of 1200-1400 oC for 1h. For comparison, another vanadate glass with the composition of xZrO2(20-x)CaO10Fe2O370V2O5 (x=0-20), abbreviated as xZCFV, was prepared under the same condition. Isothermal heat treatment was performed at 500 oC for 100 min in air. 57Fe-Mssbauer spectra were measured by constant acceleration method. 57Co(Rh) and -Fe were used as a source and a reference, respectively. Measurements of were carried out by DC four-probe method. Results and Discussion Two doublets with isomer shift () and quadrupole splitting () of 0.420.01 and 0.290.01 mm s-1, 0.340.03 and 1.480.06 mm s-1 were observed from the 57Fe-Mssbaeur spectrum of heat-treated 20ZFV glass, respectively of which is ascribed to FeIII2VV4O13 and an amorphous FeIII-VIV-O phases [3] (Fig. 1(a)). On the other hand, three paramagnetic doublets with and of 0.390.01 and 0.330.04, 0.400.01 and 0.650.04, and 0.320.01 and 1.120.03 mm s-1 were observed from 0ZCFV glass (Fig. 1(b)), which is ascribed to FeIIIVVO4 [4]. These results may suggest

that when a glass contained few network-modifiers (NWM), iron ion partially reduces vanadium from VV to VIV.

Figure 1. 57Fe-Mssbauer spectra of (a) 20ZFV

and (b) 0ZCFV heated at 500 oC for 100min. A gradual increase in was observed from 6.310-5 to 2.910-3 S cm-1 with increasing ZrO2 content from 0 to 30 mol%. However, the drastic increase in due to HT, which could be observed in 0ZCFV, did not occur for xZFV glass. It is concluded that introduction of zirconia into vanadate glass results in higher conductivity without HT. In addition, we found that it is favorable for vanadate glass to contain less than 20 mol% of Ca2+ for the drastic increase in caused by HT. References [1] N.F. Mott, Adv. Phys. V. 16 No.61 (1967) 49 [2] T. Nishida, Jpn. Patent (2006) No. 3854985. [3] A. Brckner, G.-U. Wolf, M. Meisel, R. Stsser, H. Mehner, F. Majunke and M. Baerns, J. Catal. V. 154 (1995) 11 [4] S. Kubuki, K. Matsuda, K. Akiyama and T. Nishida, J. Radioanal. Nucl. Chem. V. 299 (2014) 453

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T07IndustrialApplications

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T08MagnetismandMagneticMaterials

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T08: CORRELATION BETWEEN MILLING TIME OF POWDER, AND THE

TEMPERATURE OF SUBSTRATE ON THE PROPERTIES OF NdFe THIN FILMS Y.A. Rojas Martnez, D. Oyola Lozano, H. Bustos Rodrguez

Department of Physics, University of Tolima, A.A. 546, Ibagu, Colombia *Corresponding author: e-mail: yarojas@ut.edu.co Keywords: Mssbauer spectrometry, Thin films, Mechanical alloy Topic: T08- Magnetism and Magnetic Materials In this study we report the structural and magnetic properties, obtained by 57Fe Mssbauer spectrometry (MS) and X-ray diffraction (XRD), and Physical Properties Measurement System (PPMS), of amorphous rare-earth transition metal alloys of compositions Nd0.257Fe0.743 prepared by mechanical alloying during 12, 24, and 48 hours to study the influence of the milling time of powders. The films were prepared by DC sputtering technique deposited on Kapton substrate, at substrate temperature varying at 77K,300K, 450K, To study the influence of the temperature substrate in their magnetic and structural properties. The X-rays results show that the -Fe and amorphous phase in all the samples are present. The first decreases while the second one increase, with increase of the milling time and the substrate temperature, respectively. Mossbauer spectrometry results show that the amorphous phase in samples are ferromagnetic and appears as a hyperfine field distribution and a broad doublet. When the milling time and the substrate temperature increases, the paramagnetic contribution increase too.

31

T08: IN -Fe2MnGa COMPOUND DO Fe AND Mn ORDER MAGNETICALLY AT THE SAME TEMPERATURE? DO THEY COUPLE PARALLEL OR

ANTIPARALLEL AT LOW TEMPERATURES? Edson Caetano Passamani

Depto de Fsica, Universidade Federal do Esprito Santo, 29075-910, Vitria, ES, Brazil Heusler alloys (HAs) are generically represented by the stoichiometric X2YZ formula, where X and Y atoms are, in principle, d-elements with more than half-filled and less than half-filled shells, respectively and Z are atoms with sp-shell electrons. This series of compounds has potential for technological application including spintronics devices. They usually stabilize at room temperature, either with L21-type (Fm3m number 225) full Heusler alloy (HA) or with C1b-type (F-43m) half-HA structure. Specifically, for the Fe2MnGa HA there are several controversies reported in literature; either related with its crystal structure or with its magnetic state at high and low temperatures (above 300 K and below 200 K). According to first principles calculations, Fe2MnGa HA should have the stable L21-type structure, as typically found in most of full HAs. However, it was recently reported the L12-type as its stable configuration, determined by electronic calculation. Experimental results seem also to be contradictory from the structural viewpoint because the samples are no single crystalline phase. From magnetic viewpoint, a ferromagnetic (FM) state is expected to be the ground state for the L21-type as well for the L12-type structure; a ferrimagnetic (FI) configuration is 0.02 eV high in energy. An additional controversy is related to the existence of exchange bias (EB) effect, which is attributed to an antiferromagnetic (AF) state that appears at low temperatures. However, there is no direct proof for a coexistence of FM and AF states in this material, except for the presence of the loop shifting effect at low temperatures. Then, as the -Fe2MnGa HA has iron as a natural constituent, 57Fe Mossbauer spectroscopy could be a suitable method to investigate Fe environment and its magnetic state, considering that Mn atoms govern the alloy magnetism. Thus, in this work, bulk and local magnetic properties of the single phase polycrystalline -Fe2MnGa Heusler alloy have been studied in a broad temperature range and under high applied magnetic fields using X-ray diffraction, magnetization measurements and Mssbauer spectroscopy. X-ray diffraction data of the -Fe2MnGa alloy indicate stabilization of a L12-type structure and no structural phase transformation induced by thermal effect. While magnetization experiments have shown that the Mn sublattice is ferromagnetic well above 300 K, 57Fe Mssbauer spectroscopy indicates that Fe-sublattice orders magnetically at 200 K and couple antiparallel with Mn sublattice. This ferrimagnetic state is responsible for the magnetization reduction in low temperatures observed at low temperature. Due to high magnetic anisotropy of this material, a large vertical (magnetization-axis) and horizontal (field-axis) magnetization loop shift effects are observed in field-cool process for fields up to 5T, consequently they cannot be purely attributed to the exchange bias effect, as reported in literature for this Heusler compound.

32

T08: MAGNETIC PROPERTIES OF TWO CORE/SHELL NANOPARTICLES COUPLED VIA DIPOLAR INTERACTION W. R.Aguirre-Contreras1,*, and A.M. Schnhbel1

1Grupo de Metalurgia y Transiciones de Fase, Facultad de Ciencias Naturales y Exactas, Universidad del Valle. Cali, Colombia *Corresponding author: e-mail: william.aguirre@correounivalle.edu.co Keywords: Magnetic core/shell nanoparticles, Monte Carlo simulation, Metropolis algorithm, dipolar interaction, Ising Model Topic: T08- Magnetism and Magnetic Materials We have used Monte Carlo simulations by Metropolis algorithm to study the magnetic properties of two identical core/shell nanoparticles with spherical shapes. A three-dimensional Ising Model with ferromagnetic (antiferromagnetic) nearest-neighbor couplings for core (shell) has been used on a body-centered cubic lattice and we have considered that nanoparticles are coupled by dipolar interactions. Zero-field cooling simulations were performed to obtain magnetization, susceptibility and Edward-Anderson factor as a function of dimensionless temperature. We also present the phase diagram as a function of the distance between nanoparticles and radii. References [1] A. Weizenmann and W. Figueiredo. Int. Journ. of Mod. Phys. C, V. 23(08) (2012) 12400061 [2] A. Weizenmann and W. Figueiredo. Phys. A, (2010) 389 [3] Liu W, Zhong W, Du YW., J. Nanosc. Nanotechnol. 8(6) (2008) 278 [4] D. Kechrakos and K. N. Trohidou. Appl. Phys. Lett. 81 (2002) 4574

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T08: MSSBAUER AND STRUCTURAL STUDY OF ALLOYS Fe1-XVX OBTAINED BY MECHANICAL ALLOYING

Dagoberto Oyola Lozano, Yebrayl Antonio Rojas Martnez, Humberto Bustos Rodrguez 1Department of Physics, University of Tolima, A.A. 546, Ibagu, Colombia *Corresponding author: e-mail: doyola@ut.edu.co Keywords: Mechanical Alloying, Mssbauer Spectroscopy, Laves phase Topic: T08- Magnetism and Magnetic Materials In the present work we studied the structural and magnetic properties of milled powders to 12, 48 and 72 hours of the Fe1-xVx with x= 0.1, 0.3, 0.5 and 0.7 obtained by mechanical alloying. The samples were characterized by Mssbauer spectroscopy and, X-ray diffraction. For times all of milling results Mssbauer spectra reveal that the samples show a behavior paramagnetic for x>0.5, and its pattern of X-ray diffraction indicates the presence of the Fe, V and FeV phases. For times greater than 48 hours of milling Fe1-xVx system with x>0.7 tends to an amorphous structure.

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T08: MSSBAUER INVESTIGATIONS ON THE DESORBTION OF HYDROGEN AND HYDROXYL FROM THE IRON OXIDE NANOPARTICLES

L. Herojit Singh, S. S. Pati, A. C. de Oliveira and V. K. Garg Institute of Physics, University of Braslia, 70910-970 Braslia, DF, Brazil *Corresponding author: e-mail: loushambam@gmail.com Keywords: Mssbauer spectrum, reduction, topotactical transformation Topic: T08- Magnetism and Magnetic materials Magnetite (Fe3O4) due to its unique magnetic properties, it plays an important role in biological applications such as hyperthermia, gene targeting etc. Stoichiometry of magnetite dictates the magnetism of magnetite. Iron oxide nanoparticles were synthesized through precipitation of FeSO4.7H2O in the presence of NaOH maintaining the pH value of 11. XRD of the as prepared nanoparticles confirmed the single phase formation of Fe3O4 having crystallite size of 60 nm as derived using Debye Scherer formula. Mssbauer spectra of the as prepared nanoparticles and after subsequent thermally treated at various temperatures at 10-6 mbar are depicted in Fig 1. These spectra could be resolved into four subspectra. (a) IS = 0.68 mm/s ,QS = 0.03 mm/s, absorption 47%, Hint = 453 kG corresponds to Octahedral site of Fe3O4 (b) IS = 0.29 mm/s ,QS = 0.03 mm/s, absorption 26 %, Hint = 488 kG corresponds to tetrahedral site of Fe3O4 (c) The third subspectra with an area of 4 % corresponds to goethite (-FeOOH) and (d) the fourth component with 23 % area, Hint of 464 kG, QS = 0.14 mm/s and IS = 0.33 mm/s. corresponds to hematite (-Fe2O3) The presence of hematite could not be observed by XRD, because thermal treatment altered the stoichiometry of Fe3O4 with fine nanoparticles. The heat treatment at 423K reduced the octahedral component to 37 % and the tetrahedral part increased to 38%. Surfaces with defects such as oxygen vacancies dissociates from H2O that came into contact into H+ and OH- that got adsorbed resulting to hydrogenated surface. The dissociated H+ and OH- could not recombine due to the Jahn-Teller distorted surface that could kinetically hinder recombinative desorption. Mild heat treatment desorbs the H+ and OH driving away oxygen from the particles. Therefore the reduction of -FeOOH to off-stoichiometric magnetite take place at 423 K and in the process some fraction of magnetite got oxidized leading to decrease of octahedral fraction by 10 %. However thermal treatment at 423 K is

not sufficient to drive away oxygen from the non-cubic fraction and thus remains unchanged. Increase in thermal treatment temperature to 523 K reduces the non-cubic to off-stoichiometric magnetite.

Fig1. Mssbauer spectra of the nanoparticles

and the subsequent treated at various temperatures.

Further increase in the temperature i.e. at 523 K reduces -Fe2O3 and -FeOOH to off-stoichiometric magnetite. The Mssbauer spectra of the nanoparticles after subjecting to 773 K are resolved into Fe3O4 and 13 % -Fe2O3. As the temperature increases from a 773 K temperature the H and OH are desorbed from the surface of the nanoparticles causing recombination resulting in diminution of the rate of reduction of the particles. Further increase in the temperature (above 873 K) the adsorbed H and OH no more acts as the reducing agent therefore topotactical transformation of -FeOOH to -Fe2O3 takes place and the -Fe2O3 nucleates to larger particles experiencing the hyperfine field of a bulk -Fe2O3. Acknowledgements: This work was supported by CAPES project A 127-2013; LHJ and SSP thankfully acknowledge post doctoral fellowships.

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T08: MSSBAUER STUDY OF ALLOYS Fe67.5Ni32.5, PREPARED BY ALLOY MECHANICAL

E.D. Bentez Rodrguez1, H. Bustos Rodriguez1, D. Oyola Lozano1, Y. A. Rojas Martnez1 y G.A. Prez Alczar2

1Department of Physics, University of Tolima, A.A. 546, Ibagu, Colombia 2) Instituto Nacional de Investigaciones Nucleares, Departamento de Qumica, Apdo. Postal 18-1027, Col. Escandn, Deleg. M. Hidalgo, C. P. 11801, Mxico. D. F., Mxico. *Corresponding author: e-mail: edbenitezr@ut.edu.co, hbustos@ut.edu.co Keywords: Mechanical alloying, X-Ray Diffraction, FeNi alloys, Mssbauer Spectrometry Topic: T08- Magnetism and Magnetic Materials We present the study Mssbauer of the system Fe67.5Ni32.5, prepared by mechanical alloying (MA). The structural, electronic and magnetic properties of alloys were analyzed using the techniques of x-ray diffraction (XRD), spectroscopy Mssbauer (MS) and PPMS (Physical Properties Measurement System), respectively. Samples are prepared with powders of iron and nickel in high purity (99.99%), is the respective stoichiometry of powders and powders in a planetary mill of high energy, alloy during a period of 10 hours with a 20: 1 ratio, from mass to mass of dust balls. Alloys are then sieved in different mesh: 18, 35, 60, 120, 230, 400 y 500 which are respectively equivalent a: 1mm, 500 m, 250 m, 125 m, 63 m, 38 m y 25 m. Mssbauer spectra in all alloys present a ferromagnetic behavior (see figure 1). In the graphs ZFC and FC, apparently

exists in unscreened spin glass transition below 50K, which is reached to notice a bit in sample sizes between 63 and 125 micron and disappears for smaller sizes than 25 microns. This means that this phase is related to the larger particles. Besides the curve FC as low temperature is nearly constant for the first two and it may be due to magnetic dipole interaction is less intense for small particle as in this FC curve increases at low temperatures.

36

T08: SPIN DYNAMICS IN COEXISTING ANTIFERROMAGNETIC AND SPINGLASS STATES OF MULTIFERROIC LEAD PEROVSKITES

S. Chillal1, F.J. Litterst2,4 *, S.N. Gvasaliya1, T. Shaplygina3, S.G. Lushnikov3, J.A. Munevar4, E. Baggio Saitovitch4 and A. Zheludev1

1 ETH Zrich, Laboratory for Neutron Scattering and Magnetism, 8093 Zrich, Switzerland, 2 Technische Universitt Braunschweig, 38106 Braunschweig, Germany.3 Ioffe Physical-Technical Institute RAS, 194021St.Petersburg, Russia. 4Centro Brasileiro de Pesquisas Fsicas, 22290-180 Rio de Janeiro, Brazil. *Corresponding author: e-mail: j.litterst@tu-bs.de Keywords: multiferroics, spin dynamics, perovskites, Mssbauer spectroscopy Topic:T08- Magnetism and Magnetic Materials PbFe1/2Nb1/2O3 (PFN) and PbFe1/2Ta1/2O3 (PFT) belong to the family of PbBxB1-xO3 perovskites which have inherent chemical disorder at the B-site. Due to this disorder, complex magnetic phase diagrams are expected in these materials that undergo ferroelectric transitions already above room temperature. Magnetic ground states ranging from simple antiferromagnetic to incommensurate structures have been reported [1]. As recently shown for PFN and PFT via macroscopic characterization, neutron scattering and 57Fe Mssbauer spectro-scopy, both compounds reveal antiferromagnetic transitions at 145 K and 153 K, respectively, followed by a spinglass transition around 10 K, below which antiferromagnetism coexists with a spinglass [2,3]. We suggest that the mechanism which is responsible for such a non-trivial ground state can be explained by a speromagnet-like spin arrangement (Fig. (1)).

Figure 1. Schematic of the coexisting

antiferromagnetic spinglass phase in the ground state of PFN and PFT.

Mssbauer spectroscopy reveals strongly temperature dependent broadenings (Fig. (2a,b)) of magnetic hyperfine patterns. This may originate from dynamic mechanisms and some inhomogeneous broadening. Notably, there is found an unusual increase of the mean magnetic hyperfine field below 50 K (Fig. (2c))

that is accompanied by a decrease in the antiferromagnetic magnetic Bragg peak intensity as measured by neutron scattering (Fig. (2d)). This is indicative for the onset of magnetic freezing on the time scale of Mssbauer spectroscopy resembling earlier findings in re-entrant spinglass systems [4]. We shall present a coherent analysis of the spin dynamics and its temperature dependent development along the different magnetic regimes, as probed by 57Fe.

Figure 2. a), b) The distribution of hyperfine

fields in PbFe1/2Nb1/2O3 at 4K and 30K, c) temperature dependent mean magnetic

hyperfine field at the Fe3+ ion as observed by Mssbauer spectro-scopy, d) AF Bragg peak intensity measured by neutron scattering at

wave vector (, , ) References [1] G.A. Smolenskii and I.E. Chupis, Sov. Phys. Usp. 25 (1982) 475. [2] S. Chillal, et al., Phys. Rev. B 86 (2013) 220403R. [3] S. Chillal, et al., Phys. Rev. B 87 (2014) 174418. [4] R.A. Brand, et al., J. Phys. F 15 (1985) 1987, and references given there

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37

T08: STUDY OF STRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF Fe DOPED, Co DOPED, AND Fe-Co CO-DOPED ZnO

J.J. Beltrn1*, J.A. Osorio1, C.A. Barrero1 and A. Punnoose2

1Grupo de Estado Slido, Sede de Investigacin Universitaria, Universidad de Antioquia, Medelln, Colombia 2 Department of Physics, Boise State University, Boise, Idaho 83725-1570, United States *Corresponding author: E-mail address: jjbj08@gmail.com Keywords: Diluted magnetic semiconductors, ZnO, Mssbauer spectra. Topic: T08-Magnetism and Materials Magnetic. Several works have reported ferromagnetic (FM) behavior in Fe doped, Co doped and Fe-Co co-doped ZnO systems, but there are a lot of controversies about the observed ferromagnetism. Then, careful structural and magnetic investigations with high quality single-phase samples are desired to investigate in detail this controversy. In this work, we explore the effect of Fe doping, Zn1-xFexO, Co doping, Zn1-xCoxO and Fe-Co co-doping Zn1-xFexCoxO with x =0.0, 0.01, 0.03 and 0.05 on the crystallographic, structural, optical and magnetic properties of zinc oxide nanoparticles, prepared by Sol-Gel method. These fine powders of the as-obtained product, after being annealed at 550 oC for 1h, were characterized by X ray diffraction (XRD), optical absorption, X-ray photoelectronic spectroscopy (XPS), electron paramagnetic resonance (EPR) at RT and as a function of temperature, RT 57Fe Mssbauer spectroscopy and magnetic measurements as a function of applied magnetic field and as a function of temperature [1, 2]. The XRD patterns showed that the formation of hexagonal wurtzite ZnO crystal structure in all samples was discerned as the only single phase. Optical absorption results displayed that Co doped ZnO samples exhibited smaller band gaps (Eg) than Fe doped ZnO samples and that Fe-Co co-doped ZnO nanopowders showed intermediate values. In RT 57Fe Mssbauer spectra for all Zn1-xFexO samples only paramagnetic signals were detectable, ascribed to Fe3+. For x=0.05 the introduction of a third doublet was clearly necessary, which was attributed to spinel phase ZnFe2O4. In contrast, the spectra of Zn1-xFexCoxO sample did not show this third doublet, suggesting that Co ions might be preventing the formation of ZnFe2O4. XPS and EPR results showed only Co2+ ions for Zn1-xCoxO samples with x =0.01 and 0.03, and with further doping, mixed valence of Co2+ and

Co3+ were evidenced, while in Fe-Co co-doped ZnO samples this mixed valence was observed for all doping concentration. Additionally, variable temperature EPR studies in Zn1-xFexCoxO suggested that some Co2+ ions are weakly FM coupled. Interestingly, pure ZnO sample exhibited very weak ferromagnetism, which might arise from the presence intrinsic defects that can become magnetic. The RT M vs H data of all doped and co-doped samples exhibited a linear component superimposed on a saturating FM-like magnetization. The FM character of Zn1-xFexO and Zn1-xCoxO were similar to each other, but increased compared with that of undoped ZnO. Now, Zn1-xFexCoxO samples showed higher FM behavior in comparison to the presence of only one of these cations. We deem that more probably the main role of Fe3+ ions in ZnO structure may be related to the formation of defects on the surface region, while Co ions have higher effect in its electronic properties. In Zn1-xFexCoxO the magnetic signal has been interpreted in terms of the charge transfer ferromagnetism involving mixed valence ions, most likely Co3+Co2+ in addition to changes in the electronic structure associated with the presence of defects in the nanoparticles. The study suggested that the simultaneous introduction of Fe and Co ions in ZnO lattice has a strong synergistic effect because they eliminated the formation of the ZnFe2O4 and gave the strongest ferromagnetic signal in comparison to the presence of only one of these cations. References [1] J.J. Beltrn et.al J. Phys. Chem. C 118 (2014) 1320313217. [2] J.J. Beltrn et.al J. Appl. Phys. 113 (2013) 17C308.

38

T08: SYNTHESIS AND CHARACTERIZATION OF NixCo1-xFe2O4 Nanoparticles P.M.A. Caetano1, P. R. Matos1, A. S. Albuquerque1, L.E. Fernadez-Outon2, J.D. Ardisson1 and

W.A.A. Macedo1 1Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Servio de Nanotecnologia, Belo Horizonte, Minas Gerais, Brasil. 2 Universidade Federal de Mina Gerais (UFMG), Departamento de Fsica, Belo Horizonte, Minas Gerais, Brasil. *Corresponding author: e-mail: patriciamacaetano@gmail.com Keywords: Ferrite, magnetism, nanostructure Topic: T08 - Magnetism and Magnetic Materials Nanostructured magnetic systems have been intensively investigated due to the different behavior of the materials at least one of their dimensions is in the nanometer range1. Among the nanostructured materials, ferrites, iron oxides of the type MFe2O4 (M = divalent metal ion) have been widely studied due to their magnetic properties, some of which are of great potential for application in the manufacturing of sensors with high sensitivity, e.g. for biomedical applications, such as hyperthermia, among others2,3. The present work consists in the synthesis and the investigation of structural and magnetic properties of nanostructured NixCo(1-x)Fe2O4 (with x = 0, 0.25, 0.5, 0.75 and 1.0) for hyperthermia applications. Ferrite nanoparticles were synthesized by coprecipitation and calcined at 700 C, for 2 h. The nanoparticles were characterized by X-ray diffraction (XRD), Mssbauer spectroscopy and vibrating sample magnetometry (VSM). The capacity of heat generation of the ferrites, dispersed in deionized water when submitted to an AC field (198 kHz and 220 Oe), was investigated. The XRD patterns, Fig.1 (a), showed well defined peaks, indicating the formation of the desired spinel phase. The average particle size was about 30 nm as calculated from Scherrer's formula. The magnetization curves showed that the coercivity and saturation magnetization increase due to the increase of cobalt content, as can be seen in Table 1. Table 1 Saturation magnetization and coercivity of the ferrite samples

Saturation magnetization (MSat) and Coercivity (Hc)

NixCo1-xFe2O4 X=1 X=0.75 X=0.5 X=0.25 X=0

MSat (emu/g) 20 42 49 63 66

Hc (Oe) 150 490 920 1000 1413

(b) Figure 1 (a) XRD patterns and (b) Mssbauer spectra of ferrite samples studied. Mssbauer spectra of the ferrite samples, measured at 80 K, are shown in Fig.1 (b). The spectra were fitted with two sextets referring to the Fe3+ ions present in tetrahedral and octahedral sites. Samples with higher content of Ni showed significant heating, reaching temperatures higher than 50 oC after 30 min under an alternating magnetic field due to both Brownian motion and magnetisation reversal. Our results indicated that, the control of Ni and Co content, and the nanoparticle concentration, would allow for the tailoring of the heating capabilities of these ferrites being a promising material for several applications, such as hyperthermia. This work is supported by CAPES (PNPD), CNPq and FAPEMIG. References [1] Q.A. Pankhurst, J.Connolly, S.K. Jones, J. Dobson, J. Phys. D: Appl. Phys., 36, R167 (2003). [2] C.A. Sawyer, H. Habib, K. Miller, K.N. Collier, C.L. Ondeck, M.E. McHenry, J. Appl. Phys. 105, 07B320 (2009). [3] B. D. Cullity, Introduction to Magnetic Materials (Addison-Wesley, London, 1972).

39

T08: SYNTHESIS OF SILVER -COATED MAGNETITE NANOCOMPOSITE FUNCTIONALIZED BY AZADIRACTHA INDICA

J. L. Lpez1, C. Carioca Fernandes1, D. M. S Oliveira1, M. Amorim Lima1, J. H. Dias Filho2, R. Paniago3 and K. Balzuweit3

1Centro de Cincias Biolgicas e da Natureza, Ncleo de Fsica, Universidade Federal do Acre, Rio Branco, AC 69915-900, Brazil. 2) Departamento de Cincias Exatas, Universidade Estadual de Montes Claros, 39.401-089, Minas Gerais, Brazil. 3) Departamento de Fsica, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Brazil. *Corresponding author: e-mail: jorge0503@gmail.com Keywords: Nanoparticles,functionalization, Topic: T08- Magnetism and Magnetic Materials Magnetic nanoparticles of iron oxides such as magnetite (Fe3O4) were coated with silver and then functionalized with extract of Azadirachta indica (Neem) forming a composite for use as non-toxic for the control of insect pests magnetic boots. The development of these composites requires a detailed study of the synthesis and magnetic properties of the functionalized nanoparticles to be used as an insecticide. In agriculture Azadirachta indica is used as a natural pesticide [1] and it was our interest to develop functionalized composite magnetic nanoparticles to combat Spodoptera frugiperda which is a pest of major importance in maize by reducing up to 34% crop productivity. This nanobiotechnological insecticide could also be applied to other type of pest. Magnetic fluids based on Fe3O4 has been synthesized using the condensation method by coprecipitating aqueous solutions of FeSO4, HCl and FeCl3, oleic acid mixtures in NaOH at room temperature [2-3]. Coating of Fe3O4 magnetic nanoparticles was achieved by dispersing this magnetite in AgNO3 solution containing specific amount of urea in vigorous stirring and mixture of sodium hydroxide solution and polyvinyl pyrrolidone (PVP), as stabilizer polymer, was added and finally a solution glucose was mixture. In the next step magnetite-silver core-shell nanoparticles were functionalized by Azadirachta indica. Samples with an average particle diameter ~7 nm and different concentrations of extract were studied

by Mssbauer spectroscopy and dc magnetization measurements in the range of 4.2250 K. The saturation magnetization (Ms) at 4.2 K were determined from M vs 1/H plots by extrapolating the value of magnetizations to infinite fields, to 3 - 5 emu/g and coercivity to 20- 50 Oe. The low saturation magnetization value was attributed to spin noncollinearity predominantly at the surface. From the magnetization measurements a magnetic anisotropy energy constant (K) between 1.3 - 3 104 J/m3 were calculated. Fe3O4 functionalized spectra at room temperature showed a singlet due to superparamagnetic relaxation and two sextets at low temperature. The line form in spectra Mssbauer vary with the temperatures it were simulated using a model of superparamagnetic relaxation of two levels (spin ) and theory stochastic. It was taken into account that a distribution of the size of the particles that obeys a log-normal. References [1] A. H. Varella Bevilacqua H., B. Suffredini, M.M. Bernardi, Rev. Inst. Cincias da Sade; 26(2) (2008)157. [2] J. L. Lpez, J.H. Dias Filho, R. Paniago, H. D. Pfannes, K. Balzuweit, Revista ECIPer, 10(2) (2014) 5. [3] Y.M. Wang, X. Cao, G.H. Liu, R.Y. Hong, Y.M. Chen, X.F. Chen, H.Z. Li, B.Xu, D.G. Wei, J. Magn. Magn, Mater. 323 (2011) 2953.

40

T09Multilayers,ThinFilmsandArtificiallyStructuredMaterials

41

T10PhysicalMetallurgyandMaterialsScience

42

T10: MSSBAUER AND XRD CHARACTERIZATION OF THE PHASE TRANSFORMATIONS IN A Fe-Mn-Al-C AS. CAST ALLOY DURING

TRIBOLOGY TEST J. Ramos1, J. F. Piamba2, H. Snchez3, and G.A. Prez Alczar2*

1Universidad Autnoma de Occidente, Km. 2 va Jamund, Cali, Colombia 2Universidad del Valle, Departamento Fsica, A.A. 25360, Cali, Colombia 3Universidad del Valle, Escuela de Materiales, A.A. 25360, Cali, Colombia *Corresponding author: e-mail: gpgeperez@gmail.com Keywords: Fermanal steels, DRX, Mossbauer spectrometry, tribology Topic: T10- Physical Metallurgy and Materials Science In this study Fe-29Mn-6Al0,9C-1,8Mo-1,6Si-0,4Cu (%w) alloy was prepared in an induction furnace. Chemical analysis of the as-cast sample was performed by optical emission spectrometry; Pin on Disk Tribometer (ASTM G99) at room temperature was used to evaluate the mass loss. Microstructure was characterized by Optical Microscopy, Ray X Diffraction and Transmission Mossbauer Spectroscopy. The obtained microstructure of the as-cast sample is of dendritic type and its XRD pattern (not shown here) was refined with the lines of the austenite with a volumetric fraction of 99.39% and lattice parameter of 3.67 , and the lines of the martensite with a volumetric fraction of 0.61% and lattice parameters of 2.91 and 3.09 .

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sample. Fig. 1 shows the Mossbauer spectrum of the as-cast sample and it was fitted with a singlet which corresponds to the austenite. After the tribology test, using a charge of 3N, the surface of the sample was examined and in Fig. 2 its XRD pattern is shown. The refinement of this pattern was performed with the lines of the austenite phase with a volumetric fraction of 97.89% and lattice parameter of 3.67 , and also the lines of the martensite with a volumetric

fraction of 2.21% and lattices parameters of 2.90 and 3.09 .

Figure 2. XRD pattern of the surface of the as-

cast sample after the wear test. Finally Fig. 3 shows the Mossbauer spectrum of the surface of the as-cast sample after the wear test.

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as-cast sample after the wear test This spectrum was fitted with a big paramagnetic site with similar parameters of that shown in Fig. 1, which corresponds to the austenite phase of Fe and a hyperfine magnetic field distribution which is associated to the disordered martensite which appear in the surface as a consequence of the wear process. The martensite is the responsible of the hardening of the material.

43

T10: STRUCTURAL STUDY ON Li2Fe1-xNixSiO4 J.A. Jan1, M. Jimnez2, E. Flores3, A. Muoz2, J.A. Tabares4, and G.A. Prez Alczar4

1Depto. de Qumica Fsica, CITEN, Edificio de Laboratorios Cientficos-VIP, Universidad de Panam, Panam 2Depto. de Fsica, Universidad de Panam, Panam 3Escuela de Fsica, Universidad de Panam, Panam 4Departamento de Fsica, Universidad del Valle, AA 25360, Cali, Colombia *Corresponding author: e-mail: juan.jaen@up.ac.pa Keywords: Orthosilicates, Li2FeSiO4. Topic: T10- Physical Metallurgy and Materials Science Li2FeSiO4 is a promising cathode material for Li-ion battery applications [1]. This material has good electrochemical activity and high cycling stability, but poor electronic conductivity and lithium ion mobility. One manner to improve the electrochemical performance is to dope with an isovalent cation [2-4]. Li2Fe1-xNixSiO4 (x=0, 0.10, 0.15, 0.20 and 0.30) samples were prepared via solid state reaction to study the effects of doping Ni on the crystal structure of the orthosilicate. The phase structure, morphology and composition of Li2Fe1-xNixSiO4 nanocrystals were investigated by X-ray diffraction (XRD), Mssbauer spectroscopy (MS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS), respectively. Mssbauer spectra are shown en Figure 1. X-ray diffraction data accompanied by Rietveld refinement and Mssbauer measurements showed that both, the pristine and doped Li2Fe1-xNixSiO4, basically crystallize in a monoclinic structure with (P21/n) symmetry. The doped materials up to 5% mol of Ni2+ retain the monoclinic structure and lattice parameter, which indicates that doping agent introduces into the structure of Li2FeSiO4 without destroying the lattice structure. There is a small increase of volume of the unit cell and slight changes in local environments around the FeO4 and SiO4 tetrahedra with increasing Ni doping. The crystallite size calculated from the Scherrer equation is about 60 nm. Some small amounts of electrochemical deleterious impurities, Fe2+ and Fe3+ phases, and unreacted Li2SiO3 are detected. Samples doped with more than 10 mol% contain some magnetic impurity of Fe-Ni alloy as a result of the reduction of the Fe2+ provided in the raw materials by residual carbon. The in situ formed carbon may enhance the electronic conductivity of the electrode, and effectively suppresses the grain growth of Li2FeSiO4 [5-7]. Magnetic measurements

indicated that the lithium iron orthosilicate is a paramagnetic ceramic which becomes antiferromagnetic below 23 K. Nickel dopant does not modify the paramagnetic nature of this cathode material.

Figure 1. Room temperature Mssbauer spectra of Li2Fe1-xNixSiO4 samples. References [1] A. Nytn, A. Abonimrane, M. Armand, T. Gustafsson and J.O. Thomas, Electrochem. Commun. 7 (2005), 156-160. [2] Y.H. Chen, Y.M. Zhao, X.N. An, J.M. Liu, Y.Z. Dong, Electrochim. Acta 54 (2009), 5844-5850. [3] C. Deng, S. Zhang, S.Y. Yang, B.L. Fu and J. Ma, J. Power Sources 196 (2011), 386392. [4] B. Shao and I. Taniguchi, J. Power Sources, 199 (2012) 278-286. [5] L.M. Li, H.J. Guo, X.H. Li, Z.X. Wang, W.J. Peng, K.X. Xiang and X. Cao, J. Power Sources 189 (2009), 45-50. [6] Z. Yan, S. Cai, L. Miao, X. Zhou and Y. Zhao, J. Alloys Compd. 511(1) (2012), 101-106. [7] Z. Yan, S. Cai, L. Miao, X. Zhou and Y. Zhao, J. Alloys Compd. 511(1) (2012), 101-106.

44

Posters

45

T02 CHARACTERIZATIONOFNATURALZEOLITECLINOPTILOLITEFORSORPTIONOFCONTAMINATNS

E. Xingu-Contreras1, G. Garca-R1, I. Garca-Sosa2 and A. Cabral-Prieto2(*)

1Instituto Tecnolgico de Toluca, Avenida Tecnolgico S/N, Fraccionamiento. La Virgen, c. p. 52149, Metepec, Estado de Mxico, Mxico. 2) Instituto Nacional de Investigaciones Nucleares, Departamento de Qumica, Apdo. Postal 18-1027, Col. Escandn, Deleg. M. Hidalgo, C. P. 11801, Mxico. D. F., Mxico. *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: zeolites, nanomaterials, Mssbauer. Sorption. Topic: T02- Amorphous, nanocrystal ans nanoparticles Cd contaminated rivers is one of the ambient problems that society is facing since long time ago. The traditional chemical routines produce secondary to use procedures of green chemistry [1]. In this sense present study a Mexican pretreated natural zeolite, products that the environment is further contaminates. So, new methodologies are necessary to remediate these ambient problems by trying the Clinoptilolite, with adsorbed nano crystals of Fe0 is used to remove Cr(II) in aqueous phase. The characterization of this pretreated zeolitic material, before and after the sorption process was made using X-ray diffraction (XRD), Scanned electron microscopy (SEM/EDS) and Mssbauer spectroscopy. The XRD patterns of this zeolitic material are characteristic the Clinoptilolite zeolite only.

Figure 1 XRD patterns of the treated Clinoptilolite. (a) Tarjeta JCPDS, (b) natural zeolite, (c) natural zeolite with Fe0 nanoparticles. From SEM, nano particles of different size were observed ranging from 8 to 120 nm. The Mssbauer spectra of these zeolite materials may consist of a well defined quadrupole double superimposed to broad magnetic pattern. From the isothermal curves of adsorption 35 mg of Cd(II) /g of natural zeolite can be removed from aqueous media.

Figure 2. SEM image of the natural zeolite with nano particles of Fe0, prepared with 0.54 g of FeCl3 6 H2O per g of natural zeolite [2].

Figure 3. Typical Mssbauer spectrum of natural zeolite with Fe0 core-shell nano particles.

46

The sorption of Cd(II) using natural zeolite alone removes 30 mg of Cd(II)/g, suggesting that iron nano particles may favor the removal of heavy metals more efficiently. References [1] Lzar, K., Beyer, H., Onyestyk, G., Jnsson, B., Varga, L., & Pronier, S. NanoStructured Materials, 12, (1999). 155-158. [2] Yuvakkumar, R., Elango, V., Rajendran, V., & Kannan, N. Digest Journal of Nanomaterials and Biostructures", (2011). 1771-1776.

47

T02 NOVEL PROTOCOL FOR THE SOLIDSTATE SYNTHESIS OF MAGNETITE FORMEDICALPRACTICES

D.L. Paiva, A.L. Andrade, J.D. Fabris, J.D. Ardisson, and R.Z. Domingues

1Department of Chemistry CCEB, Federal University of Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil. 2Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), 39100-000 Diamantina, Minas Gerais, Brazil. 3Laboratory of Applied Physics, Center for the Development of the Nuclear Technology, 31270-901 Belo Horizonte, Minas Gerais, Brazil. 4Department of Chemistry ICEx, Federal University of Minas Gerais (UFMG), 31270-901 Belo Horizonte, Minas Gerais, Brazil. *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: Biomedicine, Nanotechnology, Sucrose Topic: T02- Amorphous, Nanocrystals and Nanoparticles Real benefits of nanotechnology both in industrial processes and in medicine are being inimitable. Reducing sizes may significantly change some physical and chemical properties, including electrical conductivity, magnetic response, active surface area, chemical reactivity, and biological activity, relatively to the corresponding characteristics of the bulk counterpart material. The way nanoparticles are synthesized may determine their morphological uniformity, their particle sizes distribution and, as a critical feature for clinical purposes, their purity. These conditions become one of the key-issues for researchers in nanoscience and developers in nanotechnology, particularly to plan the synthesis of maghemite (-Fe2O3) or magnetite (Fe3O4) with controlled form, size in the nanoscale and magnetically induced hyperthermic behavior, if the material is to be destined to medical clinical practices. This work was devoted to the synthesis of magnetite nanoparticles by reducing the chemical oxidation state of iron (III) in a commercial synthetic maghemite. The direct solid-state chemical conversion procedure that was first used by Pereira [1] to obtain magnetite by mixing and burning a natural hematite (Fe2O3) with glucose was found unsuccessful, in the present case. Instead, the magnetite could only be effectively produced by putting the reacting mixture of the starting synthetic commercial maghemite mixed with sucrose in a furnace at 400 oC for 20 min. The after-reaction residual carbon was removed with an oxidant chemical agent to render the suitably pure magnetic oxide. The samples were characterized by Mssbauer spectroscopy; powder X-ray diffraction and Fourier transform infrared (FTIR). The 298 K-Mssbauer spectrum collected for the starting maghemite and the corresponding parameters are given in Figure 1 and Table 1. Figure 2 shows the spectrum and the corresponding parameters (Table 2) for the obtained magnetite by using a mass ratio maghemite:sucrose of 1:5.

Figure 1. 298 K-Mssbauer spectrum for the starting commercial synthetic maghemite.

Table 1: Hyperfine parameters of the fitted Mssbauer spectra recorded at 298 K. */mms-1 2/mms-1 Bhf/T RA/% 0.33 0.01 50.3 77 0.30 -0.06 48.8 13

Figure 2. 298 K-Mssbauer spectra for the obtained magnetite after the calcinations of maghemite with sucrose.

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ansm

issi

on

Velocity (mm