60711 20190709135447.0 doi 10.1038/srep41732 sideral 98167 ART-2017-98167 eng León Félix, L. Structural and magnetic properties of core-shell Au/Fe 3 O 4 nanoparticles 2017 Access copy available to the general public Unrestricted We 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 B = 59 K and a relaxed state well above T 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 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. info:eu-repo/grantAgreement/ES/DGA/E26 info:eu-repo/grantAgreement/ES/MINECO/MAT2013-42551 info:eu-repo/semantics/openAccess by http://creativecommons.org/licenses/by/3.0/es/ 4.122 2017 MULTIDISCIPLINARY SCIENCES 12 / 64 = 0.188 2017 Q1 T1 1.533 2017 Multidisciplinary 2017 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Coaquira, J.A.H. Martínez, M.A.R. (orcid)0000-0003-1558-9279 Goya, G.F. Universidad de Zaragoza Mantilla, J. Sousa, M.H. Valladares, L.D.L.S. Barnes, C.H.W. Morais, P.C. 2003 395 Universidad de Zaragoza Dpto. Física Materia Condensa. Área Física Materia Condensada 7 (2017), [8 pp.] Sci. rep. Scientific reports 2045-2322 1196349 http://zaguan.unizar.es/record/60711/files/texto_completo.pdf Versión publicada 117020 http://zaguan.unizar.es/record/60711/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:60711 articulos driver 2019-07-09-11:38:43 ARTICLE