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Systematic Research on High-Field Magnetization Process in Nd_2Fe_<14>B-type Mixed Compounds

Nd_2Fe_<14>B型混合化合物高场磁化过程的系统研究

基本信息

批准号：
01540262
负责人：
KATO Hiroaki
金额：
$ 1.15万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01540262/
关键词：
Nd_2Fe_<14>B Permanent Magnet Nd-Fe-B Magnet High Magnetic Field Magnetization Curve Crystalline Electric Field Magnetic Anisotropy 希土類鉄磁石 Nd_2Fe_<14>B Nd-Fe-B型化合物 FOMP

项目摘要

(1) High-field magnetization process in R_2Fe_<14>B single crystals (R : rare earth element) has been investigated experimentally and theoretically. A wide variety of magnetizations including the first-order magnetization process (FOMP) and the spin reorientation phenomena is reproduced by the following calculation : the ferromagnetism of the Fe sublattice is treated phenomenologically, and the crystalline electric field (CEF) theory is strictly applied to the R ions which are subject to the molecular field due to the Fe sublattice.(2) The magnetic behavior of single crystal Nd_2(Fe_<1-x>Al_x)_<14>B has been studied in steady high magnetic fields up to 300 kOe. The field H_j where the FOMP occurs increases rapidly with x. The experimental data are interpreted in terms of molecular field H_m which decreases with increasing x and the CEF parameters.(3) High-field magnetization measurements on single crystals of (Nd-Y)_2Fe_<14>B and (Nd-La)_2Fe_<14>B have been performed in steady high magnetic fields. The observed data including FOMP are successfully described by a simple dilution model based on CEF and molecular field parameters obtained for Nd_2Fe_<14>B.(4) In the quasi-binary system (Nd_<1-x>Dy_x)_2Fe_<14>B, the field H_j increases rapidly with x, reaching 320 kOe for the sample with x=0.33. The spin reorientation temperature, on the other hand, decreases with increasing x. These data are well explained by a simple a simple mixture model, in which the total free energy is the simple superposition of those of the two end members, neglecting the Nd-Dy interaction.(5) The high reproducibility of the present calculations enables us that the magnetic properties of the quasi-binary system (R_<1-x>R'_x)_2Fe_<14>B can be predicted for any combination of rare earth elements R and R'.

(1)对R_2Fe_<14>B（R：稀土元素）单晶的强场磁化过程进行了实验和理论研究。通过以下计算再现了包括一级磁化过程（FOMP）和自旋重取向现象在内的各种磁化：对Fe亚晶格的铁磁性进行唯象处理，并将晶电场（CEF）理论严格应用于Fe亚晶格分子场作用下的R离子。(2)本文研究了Nd_2（Fe_<1-x>Al_x）_<14>B单晶在300 kOe的稳恒强磁场中的磁行为。FOMP产生的场H_j随x的增大而迅速增大。用分子场H_m和CEF参数解释了实验数据，H_m随x的增大而减小。(3)在稳恒强磁场下对（Nd-Y）_2Fe_<14>B和（Nd-La）_2Fe_<14>B单晶进行了强场磁化测量。用基于CEF的简单稀释模型和Nd_2Fe_ B的分子场参数成功地描述了包括FOMP在内的观测数据<14>。(4)在准二元系（Nd_<1-x>Dy_x）_2Fe_<14>B中，磁场H_j随x迅速增大，当x=0.33时达到320 kOe。另一方面，自旋重取向温度随着x的增加而降低。用一个简单的混合物模型很好地解释了这些数据，在该模型中，总自由能是两个端元的自由能的简单叠加，忽略Nd-Dy相互作用。(5)计算结果的高重复性使我们能够对稀土元素R和R '的任何组合预测准二元系（R_<1-x>R'_x）_2Fe_<14>B的磁性。