Permeability of microstrip thin films of various materials

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 mu m strip width at each optimum interlayer thickness. When the film width is reduced to 1 mu m, 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. (C) 1996 American Institute of Physics.