Room temperature Epitaxial Stabilization of a Tetragonal Phase in ARuO3 (A=Ca,Sr) Thin Films

TL;DR

This study reveals that epitaxial strain can induce a room temperature phase transition in ARuO3 thin films, transforming their structure and significantly altering their electronic and magnetic properties, enabling property tuning via substrate choice.

Contribution

It demonstrates strain-induced stabilization of a tetragonal phase in ARuO3 thin films at room temperature, a phase not stable in bulk, and explores its effects on properties.

Findings

Strain causes orthorhombic to tetragonal phase transition.

Phase transition impacts electronic and magnetic properties.

Substrate choice enables property tuning.

Abstract

We demonstrate that SrRuO3 and CaRuO3 thin films undergo a room temperature structural phase transition driven by the substrate imposed epitaxial biaxial strain. As tensile strain increases, ARuO3 (A=Ca, Sr) films transform from the orthorhombic phase which is usually observed in bulk SrRuO3 and CaRuO3 at room temperature, into a tetragonal phase which in bulk samples is only stable at higher temperatures. More importantly, we show that the observed phenomenon strongly affects the electronic and magnetic properties of ARuO3 thin films that are grown on different single crystal substrates which in turn offers the possibility to tune these properties.