Effect of strain and electric field on the electronic soft matter in manganite thin films

TL;DR

This study investigates how substrate-induced strain influences phase separation and electronic properties in manganite thin films, revealing the dominant role of long-range strain interactions in their phase behavior.

Contribution

It demonstrates the impact of strain and electric fields on phase states in manganite thin films, highlighting differences from bulk behavior and emphasizing the role of long-range strain interactions.

Findings

Fluid phase separated state forms at intermediate temperatures.

External electric field can convert FPS to metallic state.

Long-range strain interactions dominate phase separation in thin films.

Abstract

We have studied the effect of substrate-induced strain on the properties of the hole-doped manganite (La$_{1-y}$Pr$_{y}$)$_{0.67}$Ca$_{0.33}$MnO$_{3}$ ($y$ = 0.4, 0.5 and 0.6) in order to distinguish between the roles played by long-range strain interactions and quenched atomic disorder in forming the micrometer-scale phase separated state. We show that a fluid phase separated (FPS) state is formed at intermediate temperatures similar to the strain-liquid state in bulk compounds, which can be converted to a metallic state by applying an external electric field. In contrast to bulk compounds, at low temperatures a strain stabilized ferromagnetic metallic (FMM) state is formed in the $y$ = 0.4 and 0.5 samples. However, in the $y$ = 0.6 sample a static phase separated (SPS) state is formed similar to the strain-glass phase in bulk compounds. Hence, we show that long-range strain interaction plays a dominant role in forming the micrometer-scale phase separated state in manganite thin films.