RT Journal Article
T1 Sol-gel synthesis control of iron-cobalt alloy/ferrite core/shell nanoparticles supported by a carbon medium with semi-hard magnetic features
A1 Castellano Soria, Alberto
A1 López Sánchez, Jesús
A1 Serrano, Aida
A1 Gorni, Giulio
A1 Varela Del Arco, María
A1 Sardinero, Ignacio
A1 Carmona Tejero, Noemí
A1 Hernando Grande, Antonio
A1 Marín Palacios, María Pilar
A1 Navarro Palma, Elena
AB We explore a simple and optimized approach for obtaining magnetic nanoparticle-carbon composites by a novel one-pot sol-gel method. In them, various metal cations ratios of Fe3+ and Co2+ are evaluated. The ratio of Fe:Co is a critical parameter that governs the presence of different crystalline phases with tailored magnetic properties. Interestingly, the smallest introduction of Co into the synthesis (19Fe:1Co) provides an abrupt emergence of the body-centered cubic (bcc) Fe-Co alloy, instead of the orthorhombic Pnma structure characteristic of the Fe3C intermetallic compound (1Fe:0Co). Advanced structural and electronic characterizations reveal the formation of Fe-Co/Co-ferrite core/shell nanoparticle structures embedded in a carbon matrix. The sphere-like nanoparticles range from 10 to 45 nm and the shells show a spinel structure with a thickness of 2–3 nm. In addition, X-ray absorption spectroscopy unveils that the oxidation state of Fe and Co cations is close to zero, demonstrating their predominant metallic character. The magnetic properties can be modulated by a precise control of the alloy composition varying the Co content, displaying saturation magnetization values close to ∼137 emu/g. The nanoparticles are mainly single magnetic domain with a considerable coercive field (∼450 Oe), higher than those reported in the literature for Fe-Co nanoparticles. This semi-hard character is due to a notable spring exchange effect emerged by passivating the surface of Fe-Co-bcc cores with a thin Co-ferrite-like shell
PB Elsevier
SN 0925-8388
YR 2023
FD 2023-10
LK https://hdl.handle.net/20.500.14352/136666
UL https://hdl.handle.net/20.500.14352/136666
LA eng
NO A. Castellano-Soria, J. López-Sánchez, A. Serrano, G. Gorni, M. Varela, I. Sardinero, N. Carmona, A. Hernando, P. Marín, E. Navarro, Sol-gel synthesis control of iron-cobalt alloy/ferrite core/shell nanoparticles supported by a carbon medium with semi-hard magnetic features, Journal of Alloys and Compounds 959 (2023) 170244. https://doi.org/10.1016/j.jallcom.2023.170244.
NO © 2023 The Authors.FJC2020–044866-IRYC2021-031236-I
NO European Commission
NO Ministerio de Economía y Competitividad (España)
NO Agencia Estatal de Investigación (España)
NO Ministerio de Ciencia e Innovación (España)
NO Comunidad de Madrid
NO Consejo Superior de Investigaciones Científicas
DS Docta Complutense
RD 22 may 2026