Permeability of microstrip thin films of various materials

Abstract

Soft magnetic bilayered microstrip films have been studied for various materials such as Ni–Fe–Mo–Cu, Co–Zr–Mo–Ni, Fe–Si–N, and Ni–Fe in terms of their magnetization dynamics. Effects of the strip width and the interlayer thickness on permeability were investigated. An optimum interlayer thickness was found for obtaining the maximum permeability for those films except Fe–Si–N, but the optimum value differs in magnetic film material. A scanning Kerr effect microscope observation reveals that permeability variations with strip width related to changes of the dynamic domain configurations of the strips. All magnetic film materials except Fe–Si–N show a high permeability of more than 1000 at 2 μm strip width at each optimum interlayer thickness. When the film width is reduced to 1 μm, however, the permeability decreases significantly regardless of the interlayer thickness and kinds of the film materials. For such narrow strip film, a higher permeability is obtained for higher anisotropy field. It is concluded that the shape anisotropy of the micropatterned films must be controlled for achieving a higher permeability.