Phase transitions in a perovskite thin film studied by environmental in-situ heating nano-beam electron diffraction

TL;DR

This study investigates phase transitions in strained Pr$_{0.9}$Ca$_{0.1}$MnO$_3$ thin films using in-situ heating nano-beam electron diffraction, highlighting environmental control's importance to prevent irreversible structural changes.

Contribution

It demonstrates the temperature-dependent structural transition in thin films and emphasizes the critical role of environmental conditions during heating.

Findings

Identified orthorhombic to pseudo-cubic transition in thin films.

Showed environmental control prevents irreversible structural changes.

Compared thin film behavior to bulk phase diagrams.

Abstract

The rich phase diagram of bulk Pr$_{1-x}$Ca$_{x}$MnO$_3$ resulting in a high tunability of physical properties gave rise to various studies related to fundamental research as well as prospective applications of the material. Importantly, as a consequence of strong correlation effects, electronic and lattice degrees of freedom are vigorously coupled. Hence, it is debatable whether such bulk phase diagrams can be transferred to inherently strained epitaxial thin films. In this paper, the structural orthorhombic to pseudo-cubic transition for $x=0.1$ is studied in ion-beam sputtered thin films and point out differences to the respective bulk system by employing in-situ heating nano-beam electron diffraction to follow the temperature dependence of lattice constants. In addition, it is demonstrated that controlling the environment during heating, i.e. preventing oxygen loss, is crucial in order to avoid irreversible structural changes, which is expected to be a general problem of compounds containing volatile elements under non-equilibrium conditions.