Softmagnetic Properties of Amorphous Co-(Nb, Ta)-Hf Sputtered Films

Abstract

Thermal stability of sotmagnetic properties of amorphous Co-(Nb, Ta)-Hf systems with high saturation magnetization (4πM_s) as high as that of Sendust alloy was studied. It was found that Hf-containing films having high 4πM_s (∼10000 Gauss), especially Co₈₈Ta₈Hf₄ alloy, were thermally very stable even up 500°C, while the conventional Co based amorphous films with the same 4πM_s could not tolerate such high temperature annealing.
These Hf-contained films have promising properties as magnetic head core materials for high performance VTR since they can cope with high coercivity media and withstand high temperature fabrication processes.