Magnetic properties of Ni/Fe//SiO2 multilayer film

Abstract

This paper presents an experimental investigation into the magnetic properties of Ni/Fe//SiO2 multilayer films. An increase in magnetic anisotropy and a decrease in hard-axis coercivity are observed with decreasing the Ni/Fe layer thickness in Ni/Fe//SiO2 multilayer films. By sandwiching thinner Ni/Fe and 5-nm SiO2 layers together, relative permeability is tremendously increased to a range of 3500–4500. This permeability improvement corresponds well to the minor loop in the M-H characteristics. The magnetic domain observation indicates that the domain structure is widely changed, and several 180° and reduced 90° walls exist in the pole tip of thin-film head patterns. The higher relative permeability of over 3000 and the higher saturation magnetization of 1.7 T are confirmed in the thickness range of 0.1–2.0 μm.