Electric-field-induced changes of magnetic moments and magnetocrystalline anisotropy in ultrathin cobalt films

TL;DR

This paper investigates how electric fields influence magnetic moments and anisotropy in ultrathin cobalt films, revealing microscopic mechanisms behind voltage-controlled magnetic anisotropy using advanced spectroscopy.

Contribution

It demonstrates the electric-field-induced changes in orbital magnetic moments and magnetic dipole Tz terms in ultrathin Co films, providing microscopic insights into VCMA.

Findings

Orbital magnetic moment difference of 0.013μB under electric fields.

VCMA estimated through changes in orbital magnetic moments.

Magnetic dipole Tz term has a minor role in VCMA.

Abstract

In this study, the microscopic origins of the voltage-controlled magnetic anisotropy (VCMA) in 3d-ferromagnetic metals are revealed. Using in-situ X-ray fluorescence spectroscopy that provides a high quantum efficiency, electric-field-induced changes in orbital magnetic moment and magnetic dipole Tz terms in ultrathin Co films are demonstrated. An orbital magnetic moment difference of 0.013{\mu}B. was generated in the presence of electric fields of +(-)0.2 V/nm. The VCMA of Co was properly estimated by the induced change in orbital magnetic moment, according to the perturbation theory model. The induced change in magnetic dipole Tz term only slightly contributed to the VCMA in 3d-ferromagnetic metals.