The effects of buffer layers on the crystalline structures and magnetic properties of Co-rich Co-Fe and Co-Fe-Al films

Abstract

The crystalline structures and magnetic properties of Co-Fe and Co-Fe-Al films with various buffer layers (Cu, Permalloy and Zr), grown on glass or Si substrates, have been studied. It was found that the Co-Fe films on Zr underlayers exhibit very good FCC (111) orientation parallel to the film plane, whereas neither Cu nor Permalloy can suppress the intrusion of HCP phase in the Co-Fe films. Furthermore, the FCC (111) orientation is greatly enhanced by adding a small amount of Al to the Co-Fe films with Zr underlayers. The magnetic softness expected for the films with (111) orientation of the FCC phase was not attained for the Co-Fe films because of residual HCP phase and deterioration of the (111) orientation by annealing. On the other hand, the Co-Fe-Al films with Zr buffer layers, which have a single FCC phase with enhanced (111) orientation, are magnetically soft.