Strain-induced magnetic anisotropies in ultrathin epitaxial Ni_xPd_1-x alloy films

We studied the influence of alloy composition and thickness on the magnetic properties of ultrathin Ni_xPd_1-x alloy films epitaxially grown on Cu(100) and Cu₃Au(100) substrates. Our experiments show that the magnetoelastic anisotropy plays a seminal role in the competition of the different contributions to the magnetic anisotropy. Its magnitude and sign can be adjusted via the film strain that in turn depends on the alloy composition. At a fixed thickness of 9 monolayers and a Ni concentration of 87% for Cu(100) and of 50% for Cu₃Au(100) we observe an inverse spin reorientation transition (iSRT). The occurrence of the iSRT is attributed to the fact that the magnetoelastic anisotropy overcompensates all other contributions to the effective anisotropy E_eff. © 2002 American Institute of Physics.