Anisotropic Exchange Interaction between Non-magnetic Europium Cations in Eu_2O_3

TL;DR

This study investigates the electronic structure and exchange interactions in Eu2O3's cubic and hexagonal phases, revealing weak interactions in the cubic phase and significant antiferromagnetic interactions in the hexagonal phase, affecting magnetic susceptibility.

Contribution

The paper provides a detailed computational analysis of exchange interactions in Eu2O3's different phases, highlighting phase-dependent magnetic behaviors and supporting existing experimental observations.

Findings

Weak exchange interaction in cubic Eu2O3.

Significant antiferromagnetic exchange in hexagonal Eu2O3.

Implications for magnetic susceptibility behavior.

Abstract

The electronic structure of the cubic and (high pressure) hexagonal phases of Eu2O3 have been investigated by mean of full potential linearized augmented plane wave calculations, within the LDA+U method. For the cubic phase, the comparison between ferromagnetic and antiferromag- netic calculations shows that the exchange interaction is very weak and is therefore expected to have a negligible effect on the magnetic susceptibility. This is consistent with the experimental behavior of the susceptibility of solid solutions of Eu2O3 into A2O3 (A=Y, Lu, Sc). The calcu- lations performed for the high pressure hexagonal phase, on the other hand, show that there is an antiferromagnetic exchange interaction between nearest neighbor Eu ions, which should have a sizeable effect on the susceptibility. Our results allow us to discuss the existing theories.