Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets
Experimental results of the alignment dependence of the coercivity in Nd-Fe-B sintered magnets showed that the angle of magnetization reversal for anisotropically aligned magnets was bigger than that obtained from the theoretical results calculated using the postulation that every grain independentl...
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doaj-36aa6bf20cd24f90a4d178244ff1a2f82020-11-24T20:59:43ZengAIP Publishing LLCAIP Advances2158-32262018-01-0181015226015226-710.1063/1.4985740102801ADVAngular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnetsYutaka Matsuura0Tetsuya Nakamura1Kazushi Sumitani2Kentaro Kajiwara3Ryuji Tamura4Kozo Osamura5Research Institute of Applied Sciences, 49 Tanaka Ohi-cho, Sakyo-ku, Kyoto, Japan, 606-8202Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo, Hyogo, Japan, 679-5198Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo, Hyogo, Japan, 679-5198Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo, Hyogo, Japan, 679-5198Tokyo University of Science, Department of Materials Science and Technology, Faculty of Industrial Science and Technology, 6-3-1 Niijuku, Katsushika-ku, Tokyo, Japan, 125-5876Research Institute of Applied Sciences, 49 Tanaka Ohi-cho, Sakyo-ku, Kyoto, Japan, 606-8202Experimental results of the alignment dependence of the coercivity in Nd-Fe-B sintered magnets showed that the angle of magnetization reversal for anisotropically aligned magnets was bigger than that obtained from the theoretical results calculated using the postulation that every grain independently reverses its magnetization direction following the 1/cos θ law. The angles of reversed magnetization (θ1) for Nd13.48Co0.55B5.76Febal. with alignment α=0.95 and for Nd12.75Dy0.84B5.81Co0.55Febal. with α=0.96 were 30° and 36°, respectively, which were very similar to that of an ideal magnet with a Gaussian distribution (σ=31° and 44°, respectively) of the grain alignment. In this model, we postulated that every grain independently reversed according to the 1/cos θ law. The calculation results for the angular dependence of the coercivity using the values θ1=ω1(0°)=30°, σ=31° and θ1=ω1(0°)=36°, σ=44° could qualitatively and convincingly explain the observed angular dependence of the coercivity of Nd14.2B6.2Co1.0Febal. and Nd14.2Dy0.3B6.2Co1.0Febal.. It is speculated that the magnetic domain wall is pinned at grains tilted away from the easy magnetization direction, and when the magnetic domain wall de-pins from the tilted grains, the magnetic domain wall jumps through several grains. We suggest that the coercive force of the aligned magnet behaves like a low-aligned magnet owing to the magnetization reversal of the crust of the grains induced by the pinning and subsequent jumping of the magnetic domain wall.http://dx.doi.org/10.1063/1.4985740 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yutaka Matsuura Tetsuya Nakamura Kazushi Sumitani Kentaro Kajiwara Ryuji Tamura Kozo Osamura |
spellingShingle |
Yutaka Matsuura Tetsuya Nakamura Kazushi Sumitani Kentaro Kajiwara Ryuji Tamura Kozo Osamura Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets AIP Advances |
author_facet |
Yutaka Matsuura Tetsuya Nakamura Kazushi Sumitani Kentaro Kajiwara Ryuji Tamura Kozo Osamura |
author_sort |
Yutaka Matsuura |
title |
Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets |
title_short |
Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets |
title_full |
Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets |
title_fullStr |
Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets |
title_full_unstemmed |
Angular dependence of coercivity derived from alignment dependence of coercivity in Nd-Fe-B sintered magnets |
title_sort |
angular dependence of coercivity derived from alignment dependence of coercivity in nd-fe-b sintered magnets |
publisher |
AIP Publishing LLC |
series |
AIP Advances |
issn |
2158-3226 |
publishDate |
2018-01-01 |
description |
Experimental results of the alignment dependence of the coercivity in Nd-Fe-B sintered magnets showed that the angle of magnetization reversal for anisotropically aligned magnets was bigger than that obtained from the theoretical results calculated using the postulation that every grain independently reverses its magnetization direction following the 1/cos θ law. The angles of reversed magnetization (θ1) for Nd13.48Co0.55B5.76Febal. with alignment α=0.95 and for Nd12.75Dy0.84B5.81Co0.55Febal. with α=0.96 were 30° and 36°, respectively, which were very similar to that of an ideal magnet with a Gaussian distribution (σ=31° and 44°, respectively) of the grain alignment. In this model, we postulated that every grain independently reversed according to the 1/cos θ law. The calculation results for the angular dependence of the coercivity using the values θ1=ω1(0°)=30°, σ=31° and θ1=ω1(0°)=36°, σ=44° could qualitatively and convincingly explain the observed angular dependence of the coercivity of Nd14.2B6.2Co1.0Febal. and Nd14.2Dy0.3B6.2Co1.0Febal.. It is speculated that the magnetic domain wall is pinned at grains tilted away from the easy magnetization direction, and when the magnetic domain wall de-pins from the tilted grains, the magnetic domain wall jumps through several grains. We suggest that the coercive force of the aligned magnet behaves like a low-aligned magnet owing to the magnetization reversal of the crust of the grains induced by the pinning and subsequent jumping of the magnetic domain wall. |
url |
http://dx.doi.org/10.1063/1.4985740 |
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