Induced easy-axis reorientation in Ni/Pd multilayers upon Ar sputtering pressure

We have studied the easy-axis reorientation of Ni/Pd multilayer with varyin g Ar sputtering pressure. All the Ni/Pd multilayers prepared by dc-magnetro n sputtering at an Ar sputtering pressure of 2 mTorr show in-plane magnetic anisotropy. However, room-temperature perpendicular magnetic anisotropy wa s observed in Ni/Pd multilayers prepared at an Ar sputtering pressure of 7 mTorr. To understand the origin of the easy-axis reorientation from in-plan e to out-of-plane with varying the sputtering pressure, the magnetoelastic anisotropy was quantitatively determined from delicate in situ stress and e x situ magnetostriction coefficient measurements. We have found that the ob served easy-axis reorientation was ascribed to the enhancements of the surf ace anisotropy as well as the magnetoelastic anisotropy with increasing Ar sputtering pressure. (C) 2000 American Institute of Physics. [S0021-8979(00 )89208-7].