Angle-dependent X-ray magnetic circular dichroism study of enhanced perpendicular magnetic anisotropy in hybrid [CoO/Pd](2)[Co/Pd](7) multilayers

Abstract

We have investigated the angle-dependent orbital and spin magnetic moments of the [Co/Pd] multilayer (ML) films with intervening CoO layers under annealing by employing angle-dependent soft X-ray magnetic circular dichroism (XMCD). After annealing, the orbital magnetic moments of Co ions are found to be enhanced, with the maximum values along the perpendicular direction of [Co/Pd] ML, providing evidence for the origin of the improved perpendicular magnetic anisotropy (PMA) being the interface spinorbit coupling. The induced Pd polarization was observed after annealing, demonstrating the strong CoPd hybridization arising from the Co-Pd alloy formation near the interface. The angle-dependent coercivity follows the 1/ cos theta behavior, suggesting that the magnetization reversal in the hysteresis curve in [Co/Pd] ML occurs mainly through the pinning mechanism.