Using first-principles calculations to screen for fragile magnetism: Case study of LaCrGe3 and LaCrSb3

TL;DR

This study combines experimental and first-principles theoretical methods to investigate how pressure affects the fragile ferromagnetism of LaCrGe3 and LaCrSb3, revealing key electronic and structural factors influencing magnetic stability.

Contribution

It demonstrates the effectiveness of first-principles calculations in predicting pressure-induced magnetic transitions, aiding the screening of materials with fragile magnetism.

Findings

LaCrGe3's ferromagnetism transitions to paramagnetism around 7 GPa (calculated) and 2 GPa (experiment)

The proximity of Cr density of states to the Fermi surface controls magnetic properties

LaCrSb3's ferromagnetism is robust under pressure

Abstract

In this paper, we present a coupled experimental/theoretical investigation of pressure effect on the ferromagnetism of LaCrGe3 and LaCrSb3 compounds. The magnetic, electronic, elastic and mechanical properties of LaCrGe3 and LaCrSb3 at ambient condition are studied by first-principles density functional theory calculations. The pressure dependences of the magnetic properties of LaCrGe3 and LaCrSb3 are also investigated. The ferromagnetism in LaCrGe3 is rather fragile with a ferro- to paramagnetic transition at a relatively small pressure (around 7 GPa from our calculations, and 2 GPa in experiments). The key parameter controlling the magnetic properties of LaCrGe3 is found to be the proximity of the Cr DOS to the Fermi surface, a proximity that is strongly correlated to the distance between Cr atoms along the c-axis, suggesting that there would be a simple way to suppress magnetism in systems with one dimensional arrangement of magnetic atoms. By contrast, the ferromagnetism in LaCrSb3 is not fragile. Our calculation results are consistent with our experimental results and demonstrate the feasibility of using first-principles calculations to aid experimental explorations in screening for materials with fragile magnetism.