三明治结构与同轴电缆结构磁性材料巨磁阻抗效应的理论研究

根据两种具有巨磁阻抗（GMI）效应的磁性材料实验样品，提出了两种理论模型（同轴电缆结构——Cu丝外覆软磁材料的圆柱形；三明治结构——Cu或Ag为中间层外包软磁层的三明治膜），利用Maxwell方程和Landau_Lifshitz方程对其GMI效应的机理进行了理论研究.证明了两种模型的差别仅仅是形状因子的不同，从而由理论上证实了两种结构GMI效应增强的内在一致性.证实了在同种磁性材料情况下，双层结构具有结构方面的优越性.并对照实验数据讨论了参数的影响，得到与实验定性相符的结果. 关键词： 巨磁阻抗效应 三明治膜 Maxwell方程 Landau_Lifshit

Theoretical study on the giant magnetoimpedance in coaxial-cable wire and sandwi ched film

Two phenomenological models based on the experimental samples of giant magnetoimpedance (GMI) effect are proposed. The first model is a coaxial_cable wire composed of copper cylindrical wire electroplated with a soft magnetic layer, and the second is a sandwiched film structured by two soft magnetic layers, within whic h Cu or Ag serves as the central layer. Their characteristics are discussed theo retically using Maxwell equations and Landau_Lifshitz equation. It is proved tha t for the two models the origination of enhancement of GMI effect is the same, a nd the difference between them arises from the parameter of their geometry. The structure of double deck is better than a single layer for the identical magneti c materials in GMI effect. The application of the theoretical models to real mat erials is examined. Predictions by using the models are qualitatively in agreeme nt with experimental data.