Bicrystal structure CoPt biasing films on ultrathin Cr seed layers for spin-valve GMR head

Abstract

We have successfully obtained the CoPt hard magnetic thin films of Hc=2200Oe, S=0.94, and Mr=800emu/cc on ultrathin Cr seed layers for domain control of spin-valve GMR heads. This good performance is considered to be due to the bicrystal structure of CoPt films. The microstructure was strongly dependent on the surface treatment before the Cr seed layer deposition. We believe that the mixing amorphous layer due to the strong binding between Cr and AlOx, resulting in large grain size of Cr with (200) orientation, is responsible for realizing the bicrystal structure.