Clarification of Coercive Mechanism in Rare Earth Iron Nitride Sm-Fe-N magnet

稀土氮化铁Sm-Fe-N磁体矫顽机制的阐明

• 批准号: 12640351
• 负责人: FUJI Hironobu
• 金额: $ 2.11万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640351/
• 关键词: Permanent magnet; Corcivity mechanism; Sm2Fe17N3 powder; Particle size dependence; Surface cleaning effect; Nitride; 永久磁石; 保磁力機構; 磁気異方性; サマリウム鉄窒化物

For clarifying the role that the interstitial N atoms played on the microscopic scale for basic magnetism in R_2Fe_<17>N_3, we determined the enhancements of Fe magnetic moments on the crystallographically different atomic sites and crystalline electric field parameter A_2^0 upon nitrogenation by neutron diffraction studies of the rhombohedral Y_2Fe^<17> and Y_2Fe_<17>N_<3.1> and high-field magnetization measurements of single crystalline Nd_2Fe_<17> and Nd_2Fe_<17>N_3, respectively. The results obtained are compared with those estimated by the band structure calculation. For clarifying the coercivity mechanism in Sm_2Fe_<17>N_3, we also examined the particle (powder) size and surface cleaning effects on the coercive field μ_0H_c for the Sm_2Fe_<17>N_3 single crystal powder. The results indicate that μ_0H_c monotonically decreases with increasing the particle size, suggesting that the coercivity mechanism is of a nucleation type. When there are many nucleation sites on the surface of Sm_2F_<17>N_3 powder before surface cleaning, the value of μ_0H_c is relatively small and reveals strong temperature dependence, while μ_0H_c is strongly enhanced by surface cleaning, leading to relatively weak temperature dependence. In this work, we obtained the resultant maximum energu product (BJH)_<max> = 330 kJ/m3, which is the highest as far as we know.

为了阐明间隙N原子在微观尺度上对R_2Fe_N_3基本磁性的作用<17>，我们通过对菱面体Y_2Fe_3和Y_2Fe_N_3的中子衍射研究<17>和<17><3.1>对单晶Nd_2Fe_3和Nd_2Fe_N_3的高场磁化强度测量，确定了氮化对晶体学上不同原子位置上Fe磁矩<17>和晶体电场参数A_2^0的增强<17>。所得到的结果进行了比较与那些估计的能带结构计算。为了阐明Sm_2Fe_N_3的矫顽力机制<17>，我们还研究了颗粒（粉末）尺寸和表面清洗对Sm_2Fe_N_3单晶粉末矫顽场μ_0H_c的影响<17>。结果表明，μ_0H_c随颗粒尺寸的增大而单调减小，表明其结晶机制为成核型。当Sm_2F_N_3粉末表面存在较多形核点时<17>，表面清洗后μ_0H_c值较小，温度依赖性较强，而表面清洗后μ_0H_c值显著增大，温度依赖性较弱。在本工作中，我们得到了迄今为止所知的最大能量积（BJH）<max>= 330 kJ/m ~ 3。

项目成果

K. Koyama and H. Fujii: "Nitrogen gas-solid reaction process and basic magnetism of the intersfitially modified rare earth 3d-transition nitrides R_2Fe_<17>N_3 (R = Ce, Nd, Sm) and Y_2Co_<17>N_3."Phys. Rev B. 61. 9475-9493 (2000)

K. Koyama和H. Fujii：“间质改性稀土3d-过渡氮化物R_2Fe_<17>N_3（R = Ce，Nd，Sm）和Y_2Co_<17>N_3的氮气-固体反应过程和基本磁性。”

T. Ekino, H. Umeda, H. Fukuda, Y. Janssen and H. Fujii: "Gap Measurements of the Antiferromagnetic Compound Ce_2Fe_<17>"J. Magn. Soc. Japan. 23. 111-113 (1999)

T. Ekino、H. Umeda、H. Fukuda、Y. Janssen 和 H. Fujii：“反铁磁化合物 Ce_2Fe_<17> 的间隙测量”J。

H.Fujii et.al.: "Permanent Magnetic Properties in some Sm_2Fe_<17>N_3 Particles prepared by changing Mechanical Grinding Conditions"Proc. of 11th Symposium on Magnetic Anisotopy and Coercivity on Rare Earth. S155-S163 (2000)

H.Fujii等人：“通过改变机械研磨条件制备的一些Sm_2Fe_ 17 N_3颗粒中的永久磁性”Proc。

I.Sasaki, H.Fujii: "Coeroirity of Sm_2Fe_<17>N_3 particles prepared by MG coithoat exposing in air"IEEE Trans. Magn.. 35. 3319-3321 (1999)

I.Sasaki，H.Fujii：“通过MG coithoat暴露在空气中制备的Sm_2Fe_ 17 > N_3颗粒的Coeroirity”IEEE Trans。

K. Koyama, H. Fujji, T. Goto, H. Fukuda and Y. Janssen: "Magnetic phase transitions of Ce_2Fe_<17> under high pressures and high magnetic fields"Physica B. 294-295. 168-171 (2001)

K. Koyama、H. Fujiji、T. Goto、H. Fukuda 和 Y. Janssen：“高压和高磁场下 Ce_2Fe_<17> 的磁相变”Physica B. 294-295。