Pressure induced magnetic phase separation in La$_{0.75}$Ca$_{0.25}$MnO$_{3}$ manganite

TL;DR

This study investigates how pressure influences magnetic phase separation in La$_{0.75}$Ca$_{0.25}$MnO$_{3}$, revealing coexistence of magnetic phases and proposing a new pressure-temperature phase diagram.

Contribution

It provides experimental evidence of pressure-induced magnetic phase separation and introduces a new P-T phase diagram for this manganite.

Findings

Coexistence of antiferromagnetic and ferromagnetic phases at high pressure.

Pressure affects the Curie and metallization temperatures similarly.

A dynamical mean-field model reproduces the phase separation.

Abstract

The pressure dependence of the Curie temperature T$_{C}(P)$ in La$_{0.75}$Ca$_{0.25}$MnO$_{3}$ was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature T$_{IM}(P)$ \cite{irprl}. The behavior of the two temperatures appears similar over the whole pressure range suggesting a key role of magnetic double exchange also in the pressure regime where the superexchange interaction is dominant. Coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new P-T phase diagram has been proposed on the basis of the whole set of experimental data.