Publication
Title
Strongly exchange coupled core|shell nanoparticles with high magnetic anisotropy : a strategy toward rare-earth-free permanent magnets
Author
Abstract
Antiferromagnetic(AFM)|ferrimagnetic(FiM) core|shell (CS) nanoparticles (NPs) of formula Co0.3Fe0.7O|Co0.6Fe2.4O4 with mean diameter from 6 to 18 nm have been synthesized through a one-pot thermal decomposition process. The CS structure has been generated by topotaxial oxidation of the core region, leading to the formation of a highly monodisperse single inverted AFM|FiM CS system with variable AFM-core diameter and constant FiM-shell thickness (∼2 nm). The sharp interface, the high structural matching between both phases, and the good crystallinity of the AFM material have been structurally demonstrated and are corroborated by the robust exchange-coupling between AFM and FiM phases, which gives rise to one among the largest exchange bias (HE) values ever reported for CS NPs (8.6 kOe) and to a strongly enhanced coercive field (HC). In addition, the investigation of the magnetic properties as a function of the AFM-core size (dAFM), revealed a nonmonotonous trend of both HC and HE, which display a maximum value for dAFM = 5 nm (19.3 and 8.6 kOe, respectively). These properties induce a huge improvement of the capability of storing energy of the material, a result which suggests that the combination of highly anisotropic AFM|FiM materials can be an efficient strategy toward the realization of novel rare-earth-free permanent magnets.
Language
English
Source (journal)
Chemistry of materials. - Washington, D.C, 1989, currens
Publication
Washington, D.C : American Chemical Society, 2016
ISSN
0897-4756
Volume/pages
28:12(2016), p. 4214-4222
ISI
000378973100013
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
Faculty/Department
Research group
[E?say:metaLocaldata.cgzprojectinf]
ESTEEM 2 - Enabling science and technology through European electron microscopy.
NANOPYME: Nanocrystalline Permanent Magnets Based on Hybrid Metal-Ferrites
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 30.06.2016
Last edited 12.09.2017
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