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Magnetic and transport properties of diluted granular multilayers

2009Journal article Open Access
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dc.contributor.authorSilva, Hugo G.
dc.contributor.authorGomes, Henrique L.
dc.contributor.authorPogorelov, Y. G.
dc.contributor.authorPereira, L. M. C.
dc.contributor.authorKakazei, G. N.
dc.contributor.authorSousa, J. B.
dc.contributor.authorAraújo, J. P.
dc.contributor.authorMariano, José F. M. L.
dc.contributor.authorCardoso, S.
dc.contributor.authorFreitas, P. P.
dc.date.accessioned2014-01-07T11:09:42Z
dc.date.available2014-01-07T11:09:42Z
dc.date.issued2009
dc.date.updated2014-01-02T18:32:46Z
dc.description.abstractThe magnetic and transport properties of Co80Fe20t /Al2O34 nm multilayers with low nominal thicknesses t=0.7 and 0.9 nm of Co80Fe20 granular layers are studied. Magnetic studies find a superparamagnetic state above the blocking temperature Tb of field-cooled/zero-field-cooled splitting that grows with t and decreases with H. The low-voltage Ohmic tunnel transport passes to non-Ohmic IV3/2 law for applied fields above 500 V/cm. At fixed V, the temperature dependence of conductance reveals an anomalous dip around 220 K, which can be attributed to the effect of surface contamination by supercooled water. Current-in-plane tunnel magnetoresistance MR ratio tends, at lower t, to higher maximum values 8% at room temperature but to lower field sensitivity. This may indicate growing discorrelation effect e.g., between shrinking areas of correlated moments in this regime and corroborates the deficit of granule magnetization estimated from the Inoue–Maekawa MR fit, compared to that from direct magnetization measurements. MR displays a mean-field-like critical behavior when t approaches the point of superparamagnetic/ superferromagnetic transition tc1.3 nm at room temperature from below, different from the formerly reported percolationlike behavior at approaching it from above.With growing temperature, MR reveals, beyond the common decrease, an anomalous plateau from Tb30–50 K up to some higher value T150–200 K, not seen at higher t.por
dc.identifier.citationSilva, H. G.; Gomes, H. L.; Pogorelov, Y. G.; Pereira, L. M. C.; Kakazei, G. N.; Sousa, J. B.; Araújo, J. P.; Mariano, J. F. L.; Cardoso, S.; Freitas, P. P. Magnetic and transport properties of diluted granular multilayers, Journal of Applied Physics, 106, 11, 113910-113917, 2009.por
dc.identifier.doihttp://dx.doi.org/10.1063/1.3266010
dc.identifier.issn0021-8979
dc.identifier.otherAUT: HGO00803;
dc.identifier.urihttp://hdl.handle.net/10400.1/3283
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherAmerican Institute of Physicspor
dc.relationIon-implanted magnetic nanolayers of wide band gap semiconductors for spintronics applications
dc.relationEFEITOS QUÂNTICOS PARA OPTIMIZAÇÃO DE DISPOSITIVOS PARA SPINTRÓNICA
dc.titleMagnetic and transport properties of diluted granular multilayerspor
dc.typejournal article
dspace.entity.typePublication
oaire.awardTitleIon-implanted magnetic nanolayers of wide band gap semiconductors for spintronics applications
oaire.awardTitleEFEITOS QUÂNTICOS PARA OPTIMIZAÇÃO DE DISPOSITIVOS PARA SPINTRÓNICA
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/3599-PPCDT/PTDC%2FFIS%2F66262%2F2006/PT
oaire.awardURIinfo:eu-repo/grantAgreement/FCT//SFRH%2FBD%2F24190%2F2005/PT
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F35761%2F2007/PT
oaire.citation.endPage113917por
oaire.citation.issue11por
oaire.citation.startPage113910por
oaire.citation.titleJournal of Applied Physicspor
oaire.citation.volume106por
oaire.fundingStream3599-PPCDT
oaire.fundingStreamSFRH
person.familyNameSilva
person.familyNameGomes
person.familyNameMariano
person.givenNameHugo G.
person.givenNameHenrique Leonel
person.givenNameJosé
person.identifier.ciencia-id3C1C-8436-D591
person.identifier.ciencia-idDE19-7D9D-00D0
person.identifier.orcid0000-0002-6838-4827
person.identifier.orcid0000-0003-3664-4740
person.identifier.orcid0000-0002-8480-617X
person.identifier.ridO-5252-2018
person.identifier.scopus-author-id55986581800
person.identifier.scopus-author-id7005305880
person.identifier.scopus-author-id12647832000
project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.nameFundação para a Ciência e a Tecnologia
project.funder.nameFundação para a Ciência e a Tecnologia
project.funder.nameFundação para a Ciência e a Tecnologia
rcaap.rightsopenAccesspor
rcaap.typearticlepor
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