Intrinsic Coercivity in 4f-3d Intermetallic Magnets with Valence Fluctuations

10 Pages Posted: 17 Feb 2022

See all articles by Hiroaki Shishido

Hiroaki Shishido

Osaka Prefecture University

Tetsuro Ueno

affiliation not provided to SSRN

Kotaro Saito

affiliation not provided to SSRN

Masahiro Sawada

Hiroshima University

Munehisa Matsumoto

affiliation not provided to SSRN

Abstract

Temperature dependence of magnetization curves of well homogenized samples of Ce(Co1− x Cu x )5 (0 ≤ x ≤ 0.7), a family of representative 4f-3d intermetallic magnets found in rare-earth permanent magnets, is measured. A remarkable enhancement of intrinsic coercivity is observed with x = 0.3 and x = 0.4, persisting to higher temperatures. We argue that this experimental observation can be attributed to an effect of electronic correlation among 4f-electrons. That is, an intrinsic pinning seems to happen originating in an anomalously enhanced magnetic anisotropy energy contributed by a charge-transfer process between 4felectrons and 3d-electrons, of which energy scale is stronger than the conventional crystal field effects by an order of magnitude. It is demonstrated that the dominance of the 4f-3d charge-transfer process depends on the direction of magnetization in the middle of a crossover of the valence state of Ce between the localized 4f-electron state in CeCu5 and relatively delocalized 4f-electron state in CeCo5.

Keywords: rare earth permanent magnets, coercive force, soft X-ray absorption spectroscopy, DFT+U, valence fluctuations, spin-orbit interaction

Suggested Citation

Shishido, Hiroaki and Ueno, Tetsuro and Saito, Kotaro and Sawada, Masahiro and Matsumoto, Munehisa, Intrinsic Coercivity in 4f-3d Intermetallic Magnets with Valence Fluctuations. Available at SSRN: https://ssrn.com/abstract=4024875 or http://dx.doi.org/10.2139/ssrn.4024875

Hiroaki Shishido (Contact Author)

Osaka Prefecture University ( email )

1-1 Gakuen-Cho
Sakai, Osaka 599-8531
Japan

Tetsuro Ueno

affiliation not provided to SSRN ( email )

No Address Available

Kotaro Saito

affiliation not provided to SSRN ( email )

No Address Available

Masahiro Sawada

Hiroshima University ( email )

Higashihiroshima, 739-0046
Japan

Munehisa Matsumoto

affiliation not provided to SSRN ( email )

No Address Available

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