High magnetic field transport measurement of charge-ordered Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ strained thin films

TL;DR

This study explores how magnetic fields induce a phase transition from charge-ordered insulator to metal in Pr0.5Ca0.5MnO3 thin films, revealing substrate and strain effects on the critical magnetic field needed for this transition.

Contribution

It demonstrates the influence of substrate-induced strain on the magnetic-field-induced phase transition in charge-ordered manganite thin films, highlighting the role of stress in the robustness of the charge-ordered state.

Findings

Critical magnetic field for transition is lower in films than in bulk.

Transition depends on substrate type and film thickness.

Stress from thermal expansion mismatch affects charge-order stability.

Abstract

We have investigated the magnetic-field-induced phase transition of charge-ordered (CO) Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ thin films, deposited onto (100)-oriented LaAlO$_3$ and (100)-oriented SrTiO$_3$ substrates using the pulsed laser deposition technique, by measuring the transport properties with magnetic fields up to 22T. The transition to a metallic state is observed on both substrates by application of a critical magnetic field ($H_C>10T$ at 60K). The value of the field required to destroy the charge-ordered insulating state, lower than the bulk compound, depends on both the substrate and the thickness of the film. The difference of the critical magnetic field between the films and the bulk material is explained by the difference of in-plane parameters at low temperature (below the CO transition). Finally, these results confirm that the robustness of the CO state, depends mainly on the stress induced by the difference in the thermal dilatations between the film and the substrate.