Large perpendicular magnetic anisotropy of ultrathin Ru and Rh films on a NiAl(001)surface

Abstract

Using the full potential linearized augmented plane wave (FLAPW) method, the magneticproperties of two-dimensional Ru and Rh monolayers (MLs) on a NiAl(001) surface havebeen investigated. It has been found that free standing one monolayer Ru andRh films have ferromagnetic ground state with magnetic moments of 2.21 and1.48 μB, respectively. The ferromagnetism is still observed even on a Ni terminatedNiAl(001) surface, while no magnetic state is found on an Al terminatedsurface. The calculated magnetic moments of Ru and Rh atoms are 1.56 and0.88 μB, respectively. In addition, an induced magnetic moment in surface Ni is observed. Ithas been found that the free standing Ru film has perpendicular magnetizationto the film surface with a magnetocrystalline anisotropy (MCA) energy of0.66 meV/atom, while an in-planeMCA energy of 0.37 meV/atom is achieved in Rh film. Very interestingly, we find that both Ru/NiAl(001) andRh/NiAl(001) films have perpendicular magnetic anisotropy and the calculated MCAenergies are 0.66 and 1.11 meV in Ru/NiAl(001) and Rh/NiAl(001), respectively. Alongwith the magnetic anisotropy, we have presented theoretically calculated x-rayabsorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) results.