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dc.contributor.authorLeón Félix, Len
dc.contributor.authorCoaquira, JAHen
dc.contributor.authorMartínez, MARen
dc.contributor.authorGoya, GFen
dc.contributor.authorMantilla, Jen
dc.contributor.authorSousa, MHen
dc.contributor.authorDe Los Santos Valladares, Luisen
dc.contributor.authorBarnes, Crispinen
dc.contributor.authorMorais, PCen
dc.date.accessioned2017-03-14T14:02:41Z
dc.date.available2017-03-14T14:02:41Z
dc.date.issued2017-02-06en
dc.identifier.issn2045-2322
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/263099
dc.description.abstractWe present a systematic study of core-shell Au/Fe$_3$O$_4$ nanoparticles produced by thermal decomposition under mild conditions. The morphology and crystal structure of the nanoparticles revealed the presence of Au core of $d$ = (6.9 ± 1.0) nm surrounded by Fe$_3$O$_4$ shell with a thickness of ~3.5 nm, epitaxially grown onto the Au core surface. The Au/Fe$_3$O$_4$ core-shell structure was demonstrated by high angle annular dark field scanning transmission electron microscopy analysis. The magnetite shell grown on top of the Au nanoparticle displayed a thermal blocking state at temperatures below $T_\text{B}$ = 59 K and a relaxed state well above $T_\text{B}$. Remarkably, an exchange bias effect was observed when cooling down the samples below room temperature under an external magnetic field. Moreover, the exchange bias field ($H_\text{EX}$) started to appear at $T$~40 K and its value increased by decreasing the temperature. This effect has been assigned to the interaction of spins located in the magnetically disordered regions (in the inner and outer surface of the Fe$_3$O$_4$ shell) and spins located in the ordered region of the Fe$_3$O$_4$ shell.
dc.description.sponsorshipThis work was supported by the Brazilian agencies CNPq and CAPES (BEX 6932/15-0) through a financial support in the PhD Student Exchange Program performed in the Institute of Nanoscience of Aragón. The work in Spain was also supported by the Spanish Ministerio de Economia y Competitividad (MINECO) through project MAT2013-42551 and the Aragon Regional Government (DGA, Project No. E26) Technical support from LMAINA and SAI-UZ is acknowledged.
dc.languageengen
dc.language.isoenen
dc.publisherNature Publishing Group
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.rightsAttribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectstructural propertiesen
dc.subjectsynthesis and processingen
dc.titleStructural and magnetic properties of core-shell Au/Fe$_3$O$_4$ nanoparticlesen
dc.typeArticle
prism.number41732en
prism.publicationDate2017en
prism.publicationNameScientific Reportsen
prism.volume7en
dc.identifier.doi10.17863/CAM.8401
dcterms.dateAccepted2016-12-29en
rioxxterms.versionofrecord10.1038/srep41732en
rioxxterms.versionVoRen
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/en
rioxxterms.licenseref.startdate2017-02-06en
dc.contributor.orcidDe Los Santos Valladares, Luis [0000-0001-5930-9916]
dc.contributor.orcidBarnes, Crispin [0000-0001-7337-7245]
dc.identifier.eissn2045-2322
rioxxterms.typeJournal Article/Reviewen
cam.issuedOnline2017-02-06en
cam.orpheus.successThu Jan 30 12:56:35 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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Attribution 4.0 International
Except where otherwise noted, this item's licence is described as Attribution 4.0 International