Non-linear electrical response in a non-charge-ordered manganite: Pr0.8Ca0.2MnO3

TL;DR

This study reveals non-linear electrical conduction in a ferromagnetic insulator Pr0.8Ca0.2MnO3, showing that electric fields can restore double exchange interactions without charge order collapse, differing from charge-ordered manganites.

Contribution

It demonstrates non-linear conduction in a non-charge-ordered manganite and proposes a new interpretation involving restored double exchange interactions under electric fields.

Findings

Non-linear conduction observed in Pr0.8Ca0.2MnO3 without charge order collapse

Similar non-linear features to charge-ordered systems despite different mechanisms

Electric field effects may restore double exchange interactions

Abstract

Up to now, electric field induced non-linear conduction in the Pr(1-x)CaxMnO3 system has been ascribed to a current-induced destabilization of the charge ordered phase. However, for x<0.25, a ferromagnetic insulator state is observed and charge-ordering is absent whatever the temperature. A systematic investigation of the non-linear transport in the ferromagnetic insulator Pr0.8Ca0.2MnO3 shows rather similar results to those obtained in charge ordered systems. However, the experimental features observed in Pr0.8Ca0.2MnO3 are distinct in that the collapse of the CO energy gap can not be invoked as usually done in the other members of the PCMO system. We propose interpretations in which the effectiveness of the DE is restored upon application of electric field.