Gradual Enhancement of Stripe-Type Antiferromagnetism in Spin Ladder Material BaFe$_2$S$_3$ Under Pressure

TL;DR

This study investigates how pressure influences the magnetic and structural properties of BaFe₂S₃, revealing a gradual enhancement of stripe-type antiferromagnetic order experimentally, despite theoretical predictions of its reduction.

Contribution

The paper combines experimental neutron and muon measurements with first-principles calculations to clarify pressure effects on BaFe₂S₃'s magnetism, highlighting the role of electron correlations.

Findings

Stripe-type ordering temperature increases with pressure

Ordered magnetic moment remains unchanged up to 2.6 GPa

Discrepancy between experimental results and calculations explained by electron correlations

Abstract

We report pressure-dependent neutron diffraction and muon spin relaxation/rotation measurements combined with first-principles calculations to investigate the structural, magnetic, and electronic properties of BaFe$_2$S$_3$ under pressure. The experimental results reveal a gradual enhancement of the stripe-type ordering temperature with increasing pressure up to 2.6 GPa and no observable change in the size of the ordered moment. The ab initio calculations suggest that the magnetism is highly sensitive to the Fe-S bond lengths and angles, clarifying discrepancies with previously published results. In contrast to our experimental observations, the calculations predict a monotonic reduction of the ordered moment with pressure. We suggest that the robustness of the stripe-type antiferromagnetism is due to strong electron correlations not fully considered in the calculations.