Magnetic properties of Ni/Fe//SiO2multilayer film

This paper discusses the magnetic properties of ion‐beam‐sputtered Fe/SiO2 multilayer films. Decreasing Fe layer thickness, while maintaining a constant SiO2 layer thickness, results in good soft‐magnetic properties and nearly zero magnetostriction. These results are thought to be due to smaller crystal grains and a change in crystal orientation in the Fe layers. In Fe/SiO2 multilayer films consisting of 7‐nm Fe and 2.5‐nm SiO2 layers, magnetization of 1.55‐T, hard‐axis coercivity of 0.3 Oe, and relative permeability of 4000 are achieved under magnetostriction of less than ±10−6. After 250 °C annealing, relative permeability increases up to 5000. Furthermore, a magnetic domain structure with easy‐axis direction and extended 180° walls suitable for thin‐film heads can be obtained.