Quadratic X-ray magneto-optical effect in reflection at the M-edges of 3d transition metals

TL;DR

This paper reports the first observation of the quadratic x-ray magneto-optical Schaefer-Hubert effect at the M-edges of iron, revealing a magnetically induced polarization rotation useful for element-specific magnetic studies.

Contribution

First experimental demonstration of the x-ray Schaefer-Hubert effect at M-edges, supported by ab initio calculations highlighting core state hybridization effects.

Findings

Observed ca. 0.1° polarization rotation in reflection

Confirmed the effect as the x-ray Schaefer-Hubert effect

Theoretical analysis emphasizes core state hybridization

Abstract

We have observed a quadratic x-ray magneto-optical effect in near-normal incidence reflection at the M-edges of iron. The effect appears as the magnetically induced rotation of ca. 0.1$ degrees of the polarization plane of linearly polarized x-ray radiation upon reflection. A comparison of the measured rotation spectrum with results from x-ray magnetic linear dichroism data demonstrates that this is the first observation of the Schaefer-Hubert effect in the x-ray regime. Ab initio density-functional theory calculations reveal that hybridization effects of the 3p core states necessarely need to be considered when interpreting experimental data. The discovered magneto-x-ray effect holds promise for future ultrafast and element-selective studies of ferromagnetic as well as antiferromagnetic materials.