Effect of argon gas pressure and substrate temperature on magnetic properties of magnetron-sputtered SmCo thin films

Abstract

Preparation of hard magnetic SmCo thin films onto silicon substrate has been considered as one of the important steps in the realisation of magnetic MEMS devices. In this paper, we report the results of our investigations on the deposition and characterisation of these films. In particular, this paper deals with the study of the effect of argon gas pressure (10 ~ 40 mTorr) and substrate temperature (R.T. ~ 600 °C) on the composition, structure, and magnetic properties of SmCo thin films. These films were characterised using RBS, XRD and SQUID. The results indicate that the Co/Sm ratio of the films decreases with increasing argon gas pressure, but increases with increasing substrate temperature. As substrate temperature rises, both the degree of crystallinity and in-plane texturing increase, resulting in an increased in-plane intrinsic coercivity. Films prepared at lower substrate temperatures exhibit lower coercivity values due to the amorphous or partially crystallised phases in the films.