Epitaxial Stabilization of Ultrathin Films of Rare-Earth Nickelates

TL;DR

This paper demonstrates the epitaxial stabilization of ultrathin EuNiO3 films using pulse laser deposition, revealing how growth temperature correlates with lattice distortion and enabling new synthesis pathways for complex oxide perovskites.

Contribution

It introduces a systematic approach to stabilize ultrathin rare-earth nickelate films and discusses the empirical relationship between growth temperature and lattice distortion.

Findings

Optimal growth temperatures scale with the Goldschmidt tolerance factor.

Epitaxial stabilization is influenced by lattice energy and distortions.

Provides a route for synthesizing other complex oxide perovskites.

Abstract

We report on the synthesis of ultrathin films of highly distorted EuNiO3 (ENO) grown by interrupted pulse laser epitaxy on YAlO3 (YAO) substrates. Through mapping the phase space of nickelate thin film epitaxy, the optimal growth temperatures were found to scale linearly with the Goldschmidt tolerance factor. Considering the gibbs energy of the expanding film, this empirical trend is discussed in terms of epitaxial stabilization and the escalation of the lattice energy due to lattice distortions and decreasing symmetry. These findings are fundamental to other complex oxide perovskites, and provide a route to the synthesis of other perovskite structures in ultrathin-film form.