Structural and magnetic changes in CoAlZr thin films upon post annealing

Abstract

We present a study of the effect of annealing amorphous ferromagnetic thin films of Co 0.85 (Al 0.7 Zr 0.3 ) 0.15 , post deposition. The annealing was done in vacuum with no applied magnetic field. We find that already at a relatively low annealing temperature of 130 • C there is crystallite formation that introduces both structural and magnetic inhomogeneity. This does not affect the saturation magnetization strongly, but strongly affects the switching behavior and the overall effective anisotropy of the films. Further, there is a dramatic increase in magnetization damping. Thus, the annealing has a profound effect on both static and dynamic magnetic properties of the material. This is important to keep in mind for potential applications using these materials.