Superparamagnetic Ni:SiO2-C nanocomposites films synthesized by a polymeric precursor method

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dc.contributor.authorFonseca, F. C.
dc.contributor.authorJardim, R. F.
dc.contributor.authorEscote, M. T.
dc.contributor.authorGouveia, P. S.
dc.contributor.authorLeite, E. R.
dc.contributor.authorLongo, Elson [UNESP]
dc.contributor.institutionInst Pesquisas Energeticas & Nucl
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Federal do ABC (UFABC)
dc.contributor.institutionUniversidade Federal de São Carlos (UFSCar)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:32:08Z
dc.date.available2014-05-20T15:32:08Z
dc.date.issued2011-02-01
dc.description.abstractIn this work, we report on the magnetic properties of nickel nanoparticles (NP) in a SiO2-C thin film matrix, prepared by a polymeric precursor method, with Ni content x in the 0-10 wt% range. Microstructural analyses of the films showed that the Ni NP are homogenously distributed in the SiO2-C matrix and have spherical shape with average diameter of similar to 10 nm. The magnetic properties reveal features of superparamagnetism with blocking temperatures T (B) similar to 10 K. The average diameter of the Ni NP, estimated from magnetization measurements, was found to be similar to 4 nm for the x = 3 wt% Ni sample, in excellent agreement with X-ray diffraction data. M versus H hysteresis loops indicated that the Ni NP are free from a surrounding oxide layer. We have also observed that coercivity (H (C)) develops appreciably below T (B), and follows the H (C) ae [1 - (T/T (B))(0.5)] relationship, a feature expected for randomly oriented and non-interacting nanoparticles. The extrapolation of H (C) to 0 K indicates that coercivity decreases with increasing x, suggesting that dipolar interactions may be relevant in films with x > 3 wt% Ni.en
dc.description.affiliationInst Pesquisas Energeticas & Nucl, BR-05508000 São Paulo, Brazil
dc.description.affiliationUniv São Paulo, Inst Fis, BR-05315970 São Paulo, Brazil
dc.description.affiliationUniversidade Federal do ABC (UFABC), BR-09210170 Santo Andre, SP, Brazil
dc.description.affiliationUniversidade Federal de São Carlos (UFSCar), LIEC, São Carlos, SP, Brazil
dc.description.affiliationUniv Estadual Paulista, Inst Quim, Araraquara, SP, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Inst Quim, Araraquara, SP, Brazil
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
dc.format.extent703-710
dc.identifierhttp://dx.doi.org/10.1007/s11051-010-0068-2
dc.identifier.citationJournal of Nanoparticle Research. Dordrecht: Springer, v. 13, n. 2, p. 703-710, 2011.
dc.identifier.doi10.1007/s11051-010-0068-2
dc.identifier.issn1388-0764
dc.identifier.urihttp://hdl.handle.net/11449/41121
dc.identifier.wosWOS:000287860200025
dc.language.isoeng
dc.publisherSpringer
dc.relation.ispartofJournal of Nanoparticle Research
dc.relation.ispartofjcr2.127
dc.relation.ispartofsjr0,528
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectPolymeric precursor methoden
dc.subjectSpin coatingen
dc.subjectNickel nanoparticlesen
dc.subjectSuperparamagnetismen
dc.titleSuperparamagnetic Ni:SiO2-C nanocomposites films synthesized by a polymeric precursor methoden
dc.typeArtigo
dcterms.licensehttp://www.springer.com/open+access/authors+rights?SGWID=0-176704-12-683201-0
dcterms.rightsHolderSpringer
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Química, Araraquarapt

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