Fe/Ru界面对多层膜磁性的影响

Effects of Fe/Ru Interface on Magnetic Properties of Fe/Ru Multilayer

摘要:

采用高分辨透射电镜结合振动样品磁强计研究了Fe/Ru多层膜，对不同层厚的Fe/Ru多层膜的界面结构及其对磁性能的影响进行了分析。Fe层很薄时薄膜不连续，岛状分布的Fe颗粒使多层膜显示超顺磁特性。Fe/Ru界面的高分辨电镜观察发现，界面存在粗糙度的不对称性，它是多层膜中产生正磁阻的重要原因。Fe/Ru多层膜的负磁阻在退火后得到较大的提高，表明Fe/Ru多层膜的负磁阻主要来源于界面的粗糙度。

Abstract:

Fe/Ru multilayers were prepared by high vacuum e-gun evaporation system and the samples were studied by HRTEM and VSM. The interface structure of Fe/Ru multilayers with different thickness and its effects on magnetic properties were analyzed. Results show that the Fe/Ru multilayers have good periodic structure. When Fe layer is very thin, Fe layer is not continuous and the multilayer show a superparamagnetic property due to the Fe particles distributed as islands. HRTEM of Fe/Ru interface shows the difference in roughness between the two interfaces of Fe/Ru. The origin of the positive magnetoresistance (MR) is related to the difference in roughness, in which the scattering spin asymmetry is less than one. After annealing in vacuum, the negative MR of multilayer is increased greatly, indicating that it is originated from the roughness of the interlayer.