Structural dichroism in the antiferromagnetic insulating phase of V$_2$O$_3$

TL;DR

This study uses x-ray absorption spectroscopy to demonstrate that the observed dichroism in V2O3's antiferromagnetic phase originates from its structure, clarifying previous debates and suggesting further research into magnetoelectric effects.

Contribution

The paper provides definitive experimental evidence linking structural origin to dichroism in V2O3, resolving prior controversies and confirming theoretical predictions.

Findings

Dichroism in V2O3's AFI phase is structurally based.

Experimental results agree with ab-initio calculations.

Clarifies the nature of dichroism as non-reciprocal or structural.

Abstract

We performed near-edge x-ray absorption spectroscopy (XANES) at V K edge in the antiferromagnetic insulating (AFI) phase of a 2.8% Cr-doped V$_2$O$_3$ single crystal. Linear dichroism of several percent is measured in the hexagonal plane and found to be in good agreement with ab-initio calculations based on multiple scattering theory. This experiment definitively proves the structural origin of the signal and therefore solves a controversy raised by previous interpretations of the same dichroism as non-reciprocal. It also calls for a further investigation of the role of the magnetoelectric annealing procedure in cooling to the AFI phase.