Pressure-induced commensurate magnetic order in multiferroic $HoMn_2O_5$

TL;DR

This study maps the pressure-temperature phase diagram of HoMn₂O₅, revealing pressure-induced stabilization of commensurate magnetic order and its correlation with ferroelectricity, using neutron diffraction measurements.

Contribution

It provides the first detailed pressure-temperature magnetic phase diagram of HoMn₂O₅, showing pressure-induced magnetic order changes and their relation to dielectric properties.

Findings

Pressure stabilizes the commensurate magnetic phase at low temperatures.

The magnetic phase diagram aligns with the dielectric phase diagram under pressure.

Magnetic phase behavior under pressure resembles that under magnetic field.

Abstract

The pressure ($p$) -- temperature ($T$) phase diagram for microscopic magnetism in the multiferroic compound HoMn$_{2}$O$_{5}$ was established using neutron diffraction measurements under a hydrostatic pressure up to 1.25 GPa. At ambient pressure, incommensurate--commensurate--incommensurate magnetic phase transitions occur successively with decreasing temperature. Upon applying pressure, the incommensurate phase at the lowest temperature almost decreases and the commensurate phase appears. The $p$ -- $T$ phase diagram established shows excellent agreement with the recently reported $p$ -- $T$ dielectric phase diagram, where ferroelectricity is induced by applying pressure. We also found that the $p$ -- $T$ magnetic phase diagram is quite similar to the previously obtained magnetic field-temperature phase diagram.