Phase competitions in epitaxial Pr$_{0.5}$Ca$_{0.5}$MnO$_3$/La$_{0.5}$Sr$_{0.5}$MnO$_3$ superlattices

TL;DR

This study investigates charge-orbital ordering and phase competition in a superlattice of mixed manganite materials, revealing temperature-dependent incommensurability, hysteresis due to phase competition, and effects of layer thickness on orbital order.

Contribution

It provides new insights into the phase competition and orbital order behavior in epitaxial manganite superlattices, highlighting the impact of layer thickness and temperature.

Findings

Temperature-dependent incommensurability in orbital order

Large hysteresis caused by phase competition

Decoupling of orbital-ordered planes with reduced layer thickness

Abstract

We studied the charge-orbital ordering in the superlattice of charge-ordered insulating Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ and ferromagnetic metallic La$_{0.5}$Sr$_{0.5}$MnO$_3$ by resonant soft x-ray diffraction. A temperature-dependent incommensurability is found in the orbital order. In addition, a large hysteresis is observed that is caused by phase competition between insulating charge ordered and metallic ferromagnetic states. No magnetic phase transitions are observed in contrast to bulk, confirming the unique character of the superlattice. The deviation from the commensurate orbital order can be directly related to the decrease of ordered-layer thickness that leads to a decoupling of the orbital-ordered planes along the c axis.