Interplay between quadrupolar and magnetic interactions in 5$d^{1}$ double perovskite Ba$_2$MgReO$_6$ under pressure

TL;DR

This study investigates how pressure influences magnetic and quadrupolar orders in the 5d^1 double perovskite Ba$_2$MgReO$_6$, revealing a transition from quadrupolar to collinear antiferromagnetic states.

Contribution

It provides the first detailed phase diagram showing pressure-induced suppression of quadrupolar order and emergence of collinear antiferromagnetism in Ba$_2$MgReO$_6$, highlighting the interplay of multipolar interactions.

Findings

Pressure increases the transition temperature to canted antiferromagnetic order.

Quadrupolar order is suppressed above 5 GPa.

A collinear antiferromagnetic state appears at high pressure.

Abstract

We measured the electrical resistivity, AC magnetic susceptibility, and specific heat of the cubic double perovskite Ba$_2$MgReO$_6$ under pressure. The application of pressure leads to a gradual increase in the transition temperature to the canted antiferromagnetic order, while the quadrupolar order is suppressed above 5 GPa, at which a collinear antiferromagnetic state appears. The obtained unit cell volume-temperature phase diagram for the compound as well as the related compounds suggests that Ba$_2$MgReO$_6$ exists near the phase boundary between the noncollinear and the collinear antiferromagnetic order with multipole decrees of freedom.