Correlation between magnetic anisotropy and permeability of amorphous multi-layered films.

Abstract

Permeability of amorphous single and multilayered films is studied. As the uniaxial anisotropy becomes smaller, permeability along hard axis increases at low frequencies but decreases at high frequencies. The domain structure of the layered films becomes simple with decreasing the layer thickness, and the films show high permeability (>10,000) and good frequency characteristics. However, for the films with large Hk (≥1.3 Oe), the permeability dose not show clear structure dependence. A simple calculation based on Landau-Lifshitz model shows that rotational permeability at high frequencies is deteriorated when the magnetization direction is deviated from easy axis. It is found that the films having both high permeability and good frequency characteristics can be obtained by optimizing the multi-layered structure.