Magnetic properties of Fe/SiO2 multilayer film

Abstract

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.