Heterogeneous nucleation and metal-insulator transition in epitaxial films of NdNiO$_3$

TL;DR

This study examines the temperature-driven metal-insulator transition in NdNiO$_3$ thin films, revealing that epitaxial strain influences the transition and that it occurs via heterogeneous nucleation, differing from bulk behavior.

Contribution

It demonstrates that epitaxial strain affects the M-I transition in NdNiO$_3$ films and shows the transition occurs through heterogeneous nucleation, unlike in bulk samples.

Findings

Epitaxial strain broadens the M-I transition in thin films.

Supercooling is less in thin films than in bulk.

Transition occurs via heterogeneous nucleation in thin films.

Abstract

We have investigated the temperature driven first order metal-insulator (M-I) transition in thin films of NdNiO$_3$ and have compared it with the bulk behavior. The M-I transition of thin films is sensitive to epitaxial strain and a partial relaxation of epitaxial strain creates an inhomogeneous strain field in the films which broadens the M-I transition. Both the thin film and the bulk samples exhibit non equilibrium features in the transition regime which are attributed to the presence of high temperature metallic phases in their supercooled state. The degree of supercooling in the thin films is found to be much smaller than in the bulk which suggests that the metal insulator transition in the thin film occurs through heterogeneous nucleation.