Abnormal electroresistance effect induced by electric currents in La0.9Ba0.1MnO3 thin films

In this work, we report an abnormal electroresistance (ER) effect induced by electric current in La0.9Ba0.1MnO3 thin films. La0.9Ba0.1MnO3 thin films with thickness similar to 100 nm were prepared by using pulsed laser deposition technique. The transport behaviors were investigated under various applied currents in the absence of magnetic field. Electric resistance peaks at insulation-metal transition temperature. It was found that the peak value of the resistance gradually decreases with increasing current when the applied current is not too large. At this stage, the films can completely revert to their initial state after the applied current is removed. However, when the current reaches a critical value, a novel state appears, in which a remarkable resistive peak appears at temperatures well below the Curie temperature. An intriguing feature is that the appeared resistance peak at low temperatures turns out to be extremely sensitive to a weak current. Even a very small current could greatly depress the height of the peak, abnormal ER effect appears. Physics related to the appearance of the novel state and the abnormal ER effect is discussed. (C) 2007 Elsevier B.V. All rights reserved.