Study of Giant Magnetoresistance in Ferrimagnetic Multilayer Films

1.对射频溅射制备的Fe/Gd多层膜的磁性和磁输运性质进行了广泛的研究。Fe/Gd多层膜表现为“巨型”亚铁磁体，即由于界面处的反铁磁交换相互作用，Fe层和Gd层的磁化强度反平行耦合。在本研究中，自旋翻转和补偿现象的磁化在Fe/Gd多层膜中观察到。研究还表明，纵向和横向磁阻之间的交叉伴随着磁化的自旋翻转而发生.利用分子场理论预测的磁性结构计算了Fe/Gd多层膜的磁化强度随磁场和温度的变化曲线。对实验结果与计算结果进行了系统的比较。计算结果与实验符合较好，说明分子场理论对磁体的预测是有用的 ...更多信息 铁磁多层膜中IC结构。通过假设电流在每个原子层中平行流动的计算，定性地再现了磁阻的交叉。这表明交叉发生是由于自旋触发器场周围的磁结构的变化。从应用的角度来看，在室温和低场条件下实现磁化自旋翻转和磁阻交叉是必要的。我们制备了Fe/Gd双结构多层膜，其中两个不同的短周期λ_s的Fe/Gd子多层膜以长周期λ_（da_1）交替堆叠。本文研究了自旋翻转场的λ_s和λ_da_1依赖性。通过选择补偿温度接近室温的λ_s和/或选择较大的λ_（1.4），发现自旋翻转发生在室温和低于1000 e的磁场中。对Fe/Cr多层膜的巨磁电阻效应进行了初步研究。少

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