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The magnetic interactions between rare-earth and transition elements in the intermetallic compound

金属间化合物中稀土与过渡元素之间的磁相互作用

基本信息

批准号：
03452035
负责人：
NAGAI Hiroyuki
金额：
$ 0.7万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

In the final year, the remain measurements were carried out. According to the electronic resistances of R(Fe,Mn)_<12> where R is the rare earth element, the rapid increase due to the transition to the antiferromagnetic state was observed and explained by the similar method for CrMn alloy. The saturation magnetizations of RMn_<12> are smaller than the expected values for R^<3+> by assuming the antiferromagnetic coupling of Mn atoms. This fact suggests the existence of the strong interaction between R and Mn atoms. The R-Mn interaction was observed by ^<55>Mn NMR in the temperature range between T_C and T_N where T_C (<10K) is the magnetic ordering point of R atoms and T_N ( 100K) is that of Mn atoms. From the Mossbauer effect of ^<57>Fe in R(Fe,Mn)_<12>, The site preference of Fe atom was quantatively obtained. 8f-site is most preferential and 8i-site is hard. In the lower density of Fe , the population rate of Fe (8j/8f) is estimated to be about 30%.The another object of study is to develop strong ferromagnetic substances. In order to study the basic properties of permanent magnets, the ferromagnetic compound Gd_5Si_4 was selected as a start substance and substituted to increase the magnetic anisotropy. The contribution of R atom to the magnetic anisotropy was also investigated. As a result, the substance with higher Curie temperature was not found. While the magnetic moment per atom was larger than others. The strong permanent magnet is possible at low temperature. The NMR study of R_2Co_<14>B indicates the contribution to the magnetic anisotropy of Co sites. From these results the conditions of the possibility of the strong permanent magnet are pointed out.

在最后一年，进行了剩余测量。根据R（Fe，Mn）_（<12>其中R为稀土元素）的电子电阻，观察到由于向反铁磁态转变而迅速增加的现象，并用类似的方法对CrMn合金进行了解释。RMn_2的饱和磁化强度<12>小于假定Mn原子反铁磁耦合时对R^<3+>的预期值。这一事实表明，存在的R和Mn原子之间的强相互作用。在<55>T_C ~ T_N（T_C <10 K）和T_N（100 K）的温度范围内，用~ 1HMn NMR观察到了R-Mn相互作用。从<57>R（Fe，Mn）_中^ Fe<12>的穆斯堡尔效应，定量地得到了Fe原子的位置偏好。8 f-位点是最优惠的，8i-位点是硬的。在较低的Fe密度下，Fe（8 j/8 f）的布居率估计约为30%。为了研究永磁体的基本性能，选择铁磁化合物Gd_5Si_4作为起始物质，并对其进行替代以增加磁各向异性。研究了R原子对磁各向异性的贡献。结果表明，没有发现居里温度较高的物质，但原子磁矩较大。在低温下，强永磁体是可能的。R_2Co_ B的NMR研究<14>表明Co位对磁各向异性的贡献。从这些结果指出了强永磁体可能性的条件。