Supercooling and the Metal-Insulator Phase Transition of NdNiO$_{3}$

TL;DR

This study investigates the supercooling and phase transition behavior of NdNiO₃, revealing a non-equilibrium metallic state below 195 K and a sharp insulator-metal transition near 190 K, advancing understanding of first-order phase transitions.

Contribution

It provides detailed experimental insights into the supercooling and hysteresis phenomena in NdNiO₃'s metal-insulator transition, linking observations to phase transition theories.

Findings

NdNiO₃ is metallic above 195 K and insulating below.

Below 195 K, NdNiO₃ enters a non-equilibrium state that relaxes over hours.

A sharp insulator-metal transition occurs between 185 K and 195 K.

Abstract

We report the temperature and time dependence of electrical resistivity on high temperature, high oxygen pressure prepared polycrystalline samples of NdNiO_3. NdNiO_3 is metallic above 195 K and below that temperature it undergoes a transition to an insulating state. We find that on cooling NdNiO_3 below 195 K it goes into a state which is not in thermodynamic equilibrium and slowly relaxes over several hours. As we cool it further and go below about 110 K it goes into a stable insulating state. On heating the system from the insulating state towards 200 K we find that it remains stable and insulating and undergoes a rather sharp insulator to metal transition in the temperature range 185 K to 195 K. We try to make sense of these and a few other interesting observations on the basis of our current understanding of first order phase transitions, supercooling, and metal-insulator transitions.