Magnetic dichroism in angular resolved hard X-ray photoelectron spectroscopy from buried magnetic layers

TL;DR

This study demonstrates the use of hard X-ray photoelectron spectroscopy with circular polarization to detect magnetic dichroism in buried magnetic layers, revealing magnetic properties of in-depth structures with high sensitivity.

Contribution

It introduces a method combining HAXPES and angular resolution to analyze magnetic dichroism in buried layers, enabling insights into magnetic properties beneath surface layers.

Findings

Magnetic dichroism observed in Co and Fe 2p states at all angles.

Increased dichroism detected at normal emission angles.

Method achieves high energy and angular resolution for buried magnetic layers.

Abstract

This work reports on the measurement of magnetic dichroism in angular-resolved photoelectron spectroscopy from in-plane magnetized buried thin films. The high bulk sensitivity of hard X-ray photoelectron spectroscopy (HAXPES) in combination with circularly polarized radiation enables the investigation of the magnetic properties of buried layers. Angular distributions of high kinetic energy (7 to 8 keV) photoelectrons in a range of about 60 deg were recorded in parallel to the energy distribution. Depending on purpose, energy and angular resolutions of 150 to 250 meV and 0.17 to 2 deg can be accomplished simultaneously in such experiments. Experiments were performed on exchange-biased magnetic layers covered by thin oxide films. More specifically, the angular distribution of photoelectrons from the ferromagnetic layer Co2FeAl layer grown on MnIr exchange-biasing layer was investigated where the magnetic structure is buried beneath a MgO layer. Pronounced magnetic dichroism is found in the Co and Fe 2p states for all angles of emission. A slightly increased magnetic dichroism was observed for normal emission in agreement with theoretical considerations.