Two insulating phases in compressed Pr1-xCaxMnO3 thin films

TL;DR

This study investigates how hydrostatic pressure and magnetic field affect the resistivity of Pr1-xCaxMnO3 thin films, revealing phase separation and the independent tunability of insulating phases, with no pressure-induced metal-insulator transition observed.

Contribution

It demonstrates that phase separation in Pr1-xCaxMnO3 thin films can be manipulated independently by pressure and magnetic field, unlike bulk materials.

Findings

Resistivity decreases monotonically with pressure, up to 35% at 2.5 GPa.

No pressure-induced metal-to-insulator transition observed.

Phase separation involves two insulating phases with different sensitivities.

Abstract

The temperature dependent resistivity of two Pr1-xCaxMnO3 (x=0.5 and 0.4) thin films grown on LaAlO3 has been studied as a function of hydrostatic pressure (up to 2.5 GPa) and magnetic field (up to 9T). Both samples show a monotonic decrease in the resistivity with an increase in pressure, corresponding to a change of -35% at 2.5 GPa. No pressure induced metal-to-insulator transition was observed in the temperature-dependent resistivity. The non-trivial interaction between high pressure and magnetic field reveals that the effect of pressure cannot be simply rescaled to that of a specific field, as has been reported for the corresponding bulk material. We propose an interpretation of the data based on phase separation, where two different insulating phases coexist: the charge ordered phase, which is sensitive to both magnetic field and pressure, and a second insulating phase that can be tuned by magnetic field. Such a result demonstrates that phase separation can be manipulated in thin films by independent application of magnetic field and/or external pressure.