On the Structural Origin of the Single-ion Magnetic Anisotropy in LuFeO3

TL;DR

This study investigates the electronic structures of LuFeO3 thin films in different crystal phases, revealing how local environments influence magnetic anisotropy through crystal field effects and hybridizations.

Contribution

It provides a detailed analysis linking local electronic structures and hybridizations to the origin of single-ion magnetic anisotropy in LuFeO3.

Findings

Differences in spectra shape and dichroism between phases explained by crystal field and hybridization variations.

Uneven occupancy of spin minority states in Fe3+ linked to magnetic anisotropy.

Electronic structure measurements elucidate the origin of magnetic anisotropy in LuFeO3.

Abstract

Electronic structures for the conduction bands of both hexagonal and orthorhombic LuFeO3 thin films have been measured using x-ray absorption spectroscopy at oxygen K (O K) edge. Dramatic differences in both the spectra shape and the linear dichroism are observed. These differences in the spectra can be explained using the differences in crystal field splitting of the metal (Fe and Lu) electronic states and the differences in O 2p-Fe 3d and O 2p-Lu 5d hybridizations. While the oxidation states has not changed, the spectra are sensitive to the changes in the local environments of the Fe3+ and Lu3+ sites in the hexagonal and orthorhombic structures. Using the crystal-field splitting and the hybridizations that are extracted from the measured electronic structures and the structural distortion information, we derived the occupancies of the spin minority states in Fe3+, which are non-zero and uneven. The single ion anisotropy on Fe3+ sites is found to originate from these uneven occupancies of the spin minority states via spin-orbit coupling in LuFeO3.