Magnetic properties of multilayer films consisting of Fe and nonmagnetic layers

Abstract

This paper discusses a systematic investigation on the magnetic properties of multilayer films consisting of only Fe and nonmagnetic layers (Al2O3, Cu, C, Si, and Ti). Magnetostriction increases and becomes nearly zero as the Fe layer becomes thinner, regardless of the nonmagnetic species. In Fe/Al2O3 and Fe/Cu multilayer films, the magnetostriction increase is thought to be caused by the change in crystal preferred orientation of the Fe layers. By contrast, in Fe/C, Fe/Si, and Fe/Ti multilayer films, the increase is caused by the balance in positive and negative magnetostriction. Additionally, a low hard-axis coercivity of approximately 1 Oe and a relative permeability of more than 1000 can be achieved in Fe/Cu, Fe/Al2O3, and Fe/C multilayer films. These soft-magnetic properties are thought to be caused by the weak crystalline magnetic anisotropy due to small crystal grains and the magnetostatic coupling between Fe layers.