Unusual current-induced electroresistance in epitaxial thin films of La0.8Ca0.2MnO3

Abstract

The transport behavior of La0.8Ca0.2MnO3 thin films with Curie temperature TC at ~286 K has been investigated under various applied currents in the absence of magnetic field. An unusual current-induced electroresistance (ER) was observed. When the applied current density reaches a critical value, the films could not revert to the initial state. A novel state can be induced by a suitable large current, in which the insulation-metal transition temperature remains almost unchanged comparing with the initial state, whereas the value of the peak resistance is very sensitive to the applied current. Even a rather low current density can depress it significantly. ER reaches ~43% under a small current of 0.5 mA (density ~1×104 A cm–2). The observed ER effect seems to favor a percolative phase separation picture.