Controlling orbital moment and spin orientation in CoO layers by strain

TL;DR

This study demonstrates how strain in CoO thin films influences their magnetic properties by altering orbital occupation and anisotropy, offering a pathway to tailor magnetic behavior for advanced applications.

Contribution

The paper introduces a quantitative model linking strain, spin-orbit interaction, and magnetic anisotropy in CoO films, enabling controlled manipulation of magnetic moments.

Findings

Magnetic moments' magnitude and orientation depend on substrate-induced strain.

Strain affects 3d orbital occupation and magnetic anisotropy.

Control of strain can tailor magnetic properties for exchange bias applications.

Abstract

We have observed that CoO films grown on different substrates show dramatic differences in their magnetic properties. Using polarization dependent x-ray absorption spectroscopy at the Co L$_{2,3}$ edges, we revealed that the magnitude and orientation of the magnetic moments strongly depend on the strain in the films induced by the substrate. We presented a quantitative model to explain how strain together with the spin-orbit interaction determine the 3d orbital occupation, the magnetic anisotropy, as well as the spin and orbital contributions to the magnetic moments. Control over the sign and direction of the strain may therefore open new opportunities for applications in the field of exchange bias in multilayered magnetic films.