Interlayer exchange coupling and magnetic anisotropy in prototype trilayers:Ab initiotheory versus experiment

Abstract

The magnetic anisotropy energy (MAE) and the interlayer exchange coupling (IEC) of prototype ${\mathrm{Cu}}_{4}{\mathrm{Ni}}_{8}{\mathrm{Cu}}_{\mathrm{N}}{\mathrm{Ni}}_{9}/\mathrm{Cu}(001)$ trilayers are calculated using an ab initio approach based on the experimental lattice spacings. The results thereof are compared to ferromagnetic resonance experiments which allow for the quantitative determination of the MAE as well as the IEC. The tetragonal distortion of the Ni films due to the pseudomorphic growth leads to a positive MAE of the inner Ni layers favoring an out-of-plane easy axis. At the Cu/Ni interfaces a negative surface anisotropy is present which is, however, reduced compared to a Ni/vacuum interface. The MAE is clearly determined by the Ni layers only, whereas the IEC is shown to result from Ni and Cu layers at the inner Cu/Ni interfaces.