高抵抗軟磁性Fe-Al-Oグラニュラー膜の磁区構造  [in Japanese] Domain Structure of Highly Resistive Soft Magnetic Fe-Al-O Granular Films  [in Japanese]

In our previous study of Fe-Al-O high-resistivity granular films, We proposed a microscopic shape anisotropy model and successfully explaind the behavior of the uniaxial anisotropy of the films. To confirm the validity of this model, the relations between the anisotropy fields and the stiffness constants of the films were investigated by domain observation. Fe-Al-O strip samples with widths of 50μm and 10μm and thickness of 0.3μm were prepared. Their uniaxial anisotropy fields were adjusted in the range from 0.5 to 162.5 Oe, and the easy axes were set perpendicular to the stripe direction. All the domains of these samples are of a flux closure type. From the observed domain periods, the domain wall energy and stiffness constants were calculated. It was found that the exchange stiffness constants along the hard axis were smaller than those along the easy axis and much smaller than than that of the pure Fe. This result supports the proposed microscopic shape anisotropy model, and furthermore, implies that the films have a great advantage as thin-film cores in downsized elements such as recording heads and inductors.