Current driven discontinuous insulator-metal transition and colossal low-field magnetoresistance in Sm0.6Sr0.4MnO3

TL;DR

This study reveals that increasing current induces a discontinuous insulator-metal transition in Sm0.6Sr0.4MnO3, leading to colossal low-field magnetoresistance and electroresistance, with implications for understanding phase transitions in manganites.

Contribution

It demonstrates how current can induce a discontinuous phase transition and colossal magnetoresistance in Sm0.6Sr0.4MnO3, a novel observation in this material.

Findings

Resistivity transition becomes discontinuous with higher current.

Colossal low-field magnetoresistance observed at high current bias.

Electroresistance reaches -8000% at low temperature.

Abstract

It is shown that with increasing magnitude of current (I), resistivity of Sm0.6Sr0.4MnO3 transforms from a smooth to a discontinuous insulator-metal transition which is also accompanied by an abrupt decrease in temperature of the sample. We report colossal low-field magnetoresistance under a high current bias (-99% at H = 0.5 T and 70 K) and electroresistance (-8000 % at H = 0 T and 60 K) for I = 11 mA. We interpret our observations in terms of current induced supercooling of the high temperature paramagnetic phase and enlargement of volume fraction of the ferromagnetic phase under a magnetic field.