Resistivity minimum in strongly phase separated manganite thin films: impact of intrinsic and extrinsic perturbations

TL;DR

This study investigates the resistivity minimum in phase-separated manganite thin films, revealing it arises from non-equilibrium magnetic states influenced by phase coexistence and can be tuned by various perturbations.

Contribution

It demonstrates that the resistivity minimum is due to non-equilibrium magnetic states caused by phase coexistence and shows how it can be controlled by intrinsic and extrinsic factors.

Findings

Resistivity minimum results from non-equilibrium magnetic states.

Magnetic frustration from phase coexistence causes the resistivity minimum.

Perturbations like defects, thermal cycling, and magnetic field tune the resistivity minimum.

Abstract

The origin of the resistivity minimum observed in strongly phase separated manganites has been investigated in single crystalline thin films of LPCMO (x~0.42, y~0.40). The antiferromagnetic/charge ordered insulator (AFM/COI)-ferromagnetic metal (FMM) phase transition, coupled with the colossal hysteresis between the field cool cooled and field cooled warming magnetization demonstrates strongly phase separated nature, which gives rise to non-equilibrium magnetic liquid state that freezes into a magnetic glass. The thermal cycling and magnetic field dependence of the resistivity unambiguously shows that the pronounced resistivity minimum observed during warming is a consequence non-equilibrium states resulting from the magnetic frustration created by the delicate coexistence of the FMM and AFM/COI phases. The non-equilibrium states and hence the resistivity minimum is extremely sensitive to the relative fraction of the coexisting phases and can be tuned by intrinsic and extrinsic perturbations like the defect density, thermal cycling and magnetic field.