SOFT MAGNETIC PROPERTIES OF Fe-(Si_(3)N_(4), Al_(2)O_(3)) THIN FILMS

摘要

Ferrite cores have been used as head devices at high frequencies. However, it has been recognized that ferrites have the problem of low efficiency related to their low saturation magnetization. In order to solve the problem, much work has been done to develop Fe- and Co-based materials in the past several years. As results of this, Fe- and Co-based thin films with amorphous or nanocrystalline structure, which exhibit good soft magnetic properties up to 10 MHz, were developed. However, high frequency soft magnetic thin films are required to have high electrical resistivity in order to decrease the eddy current loss. Three types of thin films are considered for the very high frequency applications and they are; multilayered thin films, composite anisotropy films and granular films.[1] Among these, granular films consisting of metallic magnetic grains and intergrains with very high electrical resistivity are of great interest, because they possess very high electrical resistivity in the form of single layered film. In this work, in an effort to study a new high frequency soft magnetic thin film, Fe-(Si_(3)N_(4), Al_(2)O_(3)) thin films are investigated, in particular, the effects of the film composition, microstructure, electrical resistivity on the high frequency soft magnetic properties.