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 / American Chemical Society. - Washington, D.C., 1989, currens
| |
Publication
|
|
|
|
Washington, D.C.
:
2016
| |
ISSN
|
|
|
|
0897-4756
[print]
1520-5002
[online]
| |
DOI
|
|
|
|
10.1021/ACS.CHEMMATER.6B00623
| |
Volume/pages
|
|
|
|
28
:12
(2016)
, p. 4214-4222
| |
ISI
|
|
|
|
000378973100013
| |
Full text (Publisher's DOI)
|
|
|
|
| |
Full text (open access)
|
|
|
|
| |
|