Surface- and strain-induced anisotropy in epitaxial [formula omitted] films

Abstract

Magnetic anisotropy energy in epitaxial Cu(4 nm)/Ni 90Fe 10/Cu(160 nm)/Si(0 0 1) films as a function of the permalloy film thickness ( 2 nm⩽t Pm ⩽200 nm ) has been studied at room temperature. Magnetostatic energy keeps the magnetization within the film plane, although surface and magnetoelastic anisotropy energy favor magnetization normal to the film plane. Fitting the anisotropy vs. thickness with magnetostatic, bulk magnetoelastic and surface anisotropy energy requires K s =0.15 mJ/m 2 . Including the second-order magnetoelastic anisotropy in the fitting expression increases K s to 0.4 mJ/m 2 .