Anatomy of interfacial spin-orbit coupling in Co/Pd multilayers using X-ray magnetic circular dichroism and first-principles calculations

TL;DR

This study combines element-specific x-ray magnetic circular dichroism and first-principles calculations to analyze interfacial spin-orbit coupling in Co/Pd multilayers, revealing anisotropic orbital magnetic moments crucial for perpendicular magnetic anisotropy.

Contribution

It provides a detailed element-specific and orbital-resolved understanding of interfacial spin-orbit coupling effects in Co/Pd multilayers, highlighting the role of orbital moment anisotropy.

Findings

Co orbital magnetic moments are anisotropic

Pd orbital magnetic moments are isotropic

Interfacial orbital moments contribute to perpendicular magnetic anisotropy

Abstract

Element-specific orbital magnetic moments and their anisotropies in perpendicularly magnetised Co/Pd multilayers are investigated using Co L-edge and Pd M-edge angle-dependent x-ray magnetic circular dichroism. We show that the orbital magnetic moments in Co are anisotropic, whereas those in Pd are isotropic. The first-principles density-functional-theory calculations also suggest that the Co/Pd interfacial orbital magnetic moments in Co are anisotropic and contribute to the perpendicular magnetic anisotropy (PMA), and that the isotropic ones in Pd manipulates the Co orbitals at the interface through proximity effects. Orbital-resolved anatomy of Co/Pd interfaces reveals that the orbital moment anisotropy in Co and spin-flipped transition related to the magnetic dipoles in Pd are essential for the appearance of PMA.