Pressure-temperature phase diagram of charge ordering in Nd1/2Sr1/2MnO3

TL;DR

This study maps the pressure-temperature phase diagram of charge ordering in Nd1/2Sr1/2MnO3, revealing how external pressure suppresses charge order and induces metallization, with implications for understanding phase transitions in manganites.

Contribution

The paper provides the first detailed (p, T) phase diagram of charge ordering in Nd1/2Sr1/2MnO3 and compares its pressure dependence to related manganites, highlighting a symmetric relation in metallization parameters.

Findings

Charge-ordering temperature decreases from 160 K to 30 K under pressure.

The phase diagram of charge ordering is mapped out.

Pressure dependence of charge ordering is opposite to that of paramagnetic metallization.

Abstract

We observe how the charge-ordering (CO) temperature of Nd1/2Sr1/2MnO3 decreases with the external pressure p from 160 K at p = 0 down to 30 K at p ~ 4.5 GPa, by measuring the values p, T where the far-infrared spectral weight of the metallic phase is fully recovered. We thus determine the (p, T) phase diagram of CO in that manganite. We also find that the parameter d(lnTCO)/dp which describes this metallization from the CO phase is equal and opposite to the quantity d(lnTc)/dp which governs the metallization of the paramagnetic state at comparable Curie temperatures Tc, in similar manganites at half doping.