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

Abstract

We show that with increasing magnitude of current (I), insulator-metal (I-M) transition in Sm0.6 Sr0.4 MnO3 becomes discontinuous and shifts down in temperature, which is accompanied by an abrupt decrease in temperature of the sample while cooling. The I-M transition exhibits a hysteresis while warming. A magnetic field of μ0 H=0.5 T results in -99% magnetoresistance for I=11 mA compared to -32% for I=1 mA. Our results underscore the importance of inhomogeneous Joule heating that leads to coexistence of the high temperature paramagnetic phase with the low temperature ferromagnetic phase over a wide temperature range. © 2010 American Institute of Physics.