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Study of Giant Magnetoresistance in Ferrimagnetic Multilayer Films

亚铁磁多层膜中巨磁阻的研究

基本信息

批准号：
01460219
负责人：
FUJIMORI Hiroyasu
金额：
$ 4.8万
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 (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

1. magnetic and magnetotransport properties of Fe/Gd multilayers prepared by rf sputtering have extensively investigated. Fe/Gd multilayers have been found to behave as 'giant' ferrimagnets, that is, the magnetizations of Fe and Gd layers couple in antiparallel due to the antiferromagnetic exchange interaction at the interfaces. In the present study, spin-flop and compensation phenomena of the magnetization in Fe/Gd multilayers were observed. it was also revealed that a crossover between the longitudinal and transverse magnetoresistances occurred accompanied with the spin-flop of magnetization.2. The magnetization vs. field and vs. temperature curves in Fe/Gd multilayers were calculated using the magnetic structure predicted by the molecular field theory. The systematic comparison between the experiments and the calculations has been made. The calculated results agree fairly well with the experiments, suggesting-that the molecular field theory is useful for the prediction of the magnet … More ic structure in ferrimagnetic multilayers. The crossover of magnetoresistances was reproduced qualitatively well by the calculation on the assumption that the current flew in parallel in each atomic layer. This indicates that the crossover occurs due to the change in the magnetic structure around the spin-flop field.3. From the application point of view, it is necessary to obtain the spin-flop of magnetization and the crossover of magnetoresistances at room temperature and in low fields. We prepared Fe/Gd double structured multilayers, where the two different Fe/Gd submultilayers with a short period lambda_s were stacked alternately with a long period lambda_1. The lambda_s and lambda_1 dependences of the spin-flop field has been investigated. It has been found that the spin-flop occurs at room temperature and in a field lower than 1000e by choosing lambda_s where the compensation temperature approaches room temperature and/or by choosing large lambda_1.4. The fundamental study of giant magnetoresistance in Fe/Cr multilayers has also been made. Less

1. 对射频溅射法制备的Fe/Gd多层膜的磁性和磁输运特性进行了广泛的研究。发现Fe/Gd多层层表现为“巨型”铁磁体，即由于界面处的反铁磁交换相互作用，Fe和Gd层的磁化以反平行的方式偶联。在本研究中，观察了Fe/Gd多层膜中磁化的自旋翻转和补偿现象。研究还发现，随着磁化的自旋翻转，纵向和横向磁电阻之间会发生交叉。利用分子场理论预测的磁性结构，计算了Fe/Gd多层膜的磁化强度与场和温度的关系曲线。对实验结果和计算结果进行了系统的比较。计算结果与实验结果吻合较好，表明分子场理论可用于预测铁磁多层材料的磁体结构。假设电流在各原子层中平行流动，通过计算可以很好地再现磁电阻的交叉。这表明交叉的发生是由于自旋开关场周围的磁结构发生了变化。从应用的角度来看，需要在室温和低场条件下获得磁化的自旋翻转和磁电阻的交叉。我们制备了Fe/Gd双结构多层膜，其中两个不同的Fe/Gd亚多层膜具有短周期的lambda_s和长周期的lambda_1交替堆叠。研究了自旋翻转场的λ da_s和λ da_1依赖关系。通过选择补偿温度接近室温的λ da_s和/或选择较大的λ da_1.4，可以在室温和低于1000e的场中发生自旋触发器。本文还对铁/铬多层材料的巨磁电阻进行了基础研究。少