TY - JOUR
T1 - Coercivity Mechanism of Ga-Doped Nd-Fe-B Sintered Magnets
AU - Matsuura, Yutaka
AU - Nakamura, Tetsuya
AU - Ishigami, Keisuke
AU - Kajiwara, Kentaro
AU - Sumitani, Kazushi
AU - Tamura, Ryuji
AU - Nagae, Masahiro
AU - Osamura, Kozo
N1 - Funding Information:
ACKNOWLEDGMENT This work was supported in part by the Japan Science and Technology Agency (JST), in part by the Collaborative Research Based on Industrial Demand under Grant 20110111 and Grant JPMJSK1617, and in part by the Japan Society for the Promotion of Sciences (JSPS) Grant-in-Aid for Scientific Research (KAKENHI) under Grant 17K06781. The authors would like to thank R. Haase, Ph.D., from the Edanz Group, for editing a draft of this article.
Publisher Copyright:
© 1965-2012 IEEE.
PY - 2019/12
Y1 - 2019/12
N2 - The alignment dependence and angular dependence of coercivity (ALDC and ANDC, respectively) of aligned and isotropically aligned Ga-doped Nd14.79Ga0.57B5,24Co1.11Febal sintered magnets were analyzed, and the results were compared with those of ferrite magnets, which were reported in our previous paper. The coercivity of Ga-doped Nd-Fe-B magnets decreases as alignment improves. The ALDC of this magnet is similar to that of ferrite magnets. The angle of the magnetization-reversal area (AMRA) of the aligned Ga-doped magnets has at coercivity an angular tilt of 41.4°, which is wider than that of the ferrite magnets. The ANDC of Ga-doped Nd-Fe-B sintered magnets displays similar behavior with that of ferrite magnets but is slightly lower than that of ferrite magnets, which is expected from AMRA of Ga-doped Nd-Fe-B sintered magnets. These results support our proposed coercivity mechanism; specifically, the magnetic domain walls are pinned at grains with tilted easy magnetization directions or c-axis tilted from the easy magnetization of the magnet. When the magnetic domain walls are de-pinned from the pinning sites, they jump through several grains, thereby determining the coercivity.
AB - The alignment dependence and angular dependence of coercivity (ALDC and ANDC, respectively) of aligned and isotropically aligned Ga-doped Nd14.79Ga0.57B5,24Co1.11Febal sintered magnets were analyzed, and the results were compared with those of ferrite magnets, which were reported in our previous paper. The coercivity of Ga-doped Nd-Fe-B magnets decreases as alignment improves. The ALDC of this magnet is similar to that of ferrite magnets. The angle of the magnetization-reversal area (AMRA) of the aligned Ga-doped magnets has at coercivity an angular tilt of 41.4°, which is wider than that of the ferrite magnets. The ANDC of Ga-doped Nd-Fe-B sintered magnets displays similar behavior with that of ferrite magnets but is slightly lower than that of ferrite magnets, which is expected from AMRA of Ga-doped Nd-Fe-B sintered magnets. These results support our proposed coercivity mechanism; specifically, the magnetic domain walls are pinned at grains with tilted easy magnetization directions or c-axis tilted from the easy magnetization of the magnet. When the magnetic domain walls are de-pinned from the pinning sites, they jump through several grains, thereby determining the coercivity.
KW - Coercivity
KW - coercivity mechanism
KW - magnet
KW - Nd-Fe-B magnet
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U2 - 10.1109/TMAG.2019.2940205
DO - 10.1109/TMAG.2019.2940205
M3 - Article
AN - SCOPUS:85077497736
SN - 0018-9464
VL - 55
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 12
M1 - 8902247
ER -