Large orbital magnetic moment in VI3

TL;DR

This paper provides direct experimental evidence of a large orbital magnetic moment in V3+ ions within the van der Waals ferromagnet VI3, resolving a long-standing question about its magnetic nature.

Contribution

It is the first to directly measure and confirm the sizable orbital magnetic moment of V3+ ions in VI3 using XMCD and theoretical simulations.

Findings

V3+ ions have an exceptionally large orbital magnetic moment.

Two V sites exhibit different orbital occupations and magnetic moments.

Results reconcile the large magnetocrystalline anisotropy with the magnetic moment measurements.

Abstract

The existence of the V3+ ion orbital moment is the open issue of the nature of magnetism in the van der Waals ferromagnet VI3. The huge magnetocrystalline anisotropy in conjunction with the significantly reduced ordered magnetic moment compared to the spin-only value provides strong but indirect evidence of a significant V orbital moment. We used the unique capability of X-ray magnetic circular dichroism to determine the orbital component of the total magnetic moment and provide for the first time a direct proof of an exceptionally sizable orbital moment of the V3+ ion in VI3. Our ligand field multiplet simulations of the XMCD spectra in synergy with the results of DFT calculations agree with the existence of two V sites with different orbital occupations and therefore different OM magnitudes in the ground state.