Determination of the single-ion anisotropy energy in a S = 5/2 kagome antiferromagnet using X-ray absorption spectroscopy

TL;DR

This study uses x-ray absorption spectroscopy to accurately measure the single-ion anisotropy energy in a high-spin S=5/2 kagome antiferromagnet, revealing its role in the material's magnetic properties.

Contribution

It introduces a method combining x-ray absorption and ligand-field multiplet calculations to determine single-ion anisotropy in high-spin systems.

Findings

Quantified ligand-metal hybridization and anisotropy energy.

Linked single-ion anisotropy to spin-wave dispersion features.

Validated the approach with experimental data.

Abstract

We report x-ray absorption and x-ray linear dichroism measurements at the Fe L2,3 edges of the geometrically frustrated systems of potassium and hydronium iron jarosite. Comparison with simulated spectra, involving ligand-field multiplet calculations modelling the 3d-2p hybridization between the iron ion and the oxygen ligands, has yielded accurate estimates for the ligand metal-ion hybridization and the resulting single-ion crystal field anisotropy energy. Using this method we provide an experimentally verified scenario for the appearance of a single-ion anisotropy in this nominally high-spin 3d5 orbital singlet 6S system, which accounts for features of the spin-wave dispersion in the long-range ordered ground state of potassium iron jarosite.