Induced easy-axis reorientation in NiÕPd multilayers upon Ar sputtering pressure

We have studied the easy-axis reorientation of Ni/Pd multilayer with varying Ar sputtering pressure. All the Ni/Pd multilayers prepared by dc-magnetron sputtering at an Ar sputtering pressure of 2 mTorr show in-plane magnetic anisotropy. However, room-temperature perpendicular magnetic anisotropy was 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-plane to out-of-plane with varying the sputtering pressure, the magnetoelastic anisotropy was quantitatively determined from delicate in situ stress and ex situ magnetostriction coefficient measurements. We have found that the observed easy-axis reorientation was ascribed to the enhancements of the surface anisotropy as well as the magnetoelastic anisotropy with increasing Ar sputtering pressure. © 2000 American Institute of Physics. @S0021-8979~00!89208-7#