Current induced abnormal electroresistance effect observed in epitaxial La0.9Hf0.1MnO3 thin films

La0.9Hf0.1MnO3 thin films with thickness 100nm were prepared by using a pulsed laser deposition technique. Transport behaviors were investigated under various applied currents without an applied magnetic field. When the applied current is not too large, the peak value of the resistance gradually decreases with increasing current, demonstrating a normal electroresistance (ER) effect. However, when the current reaches a critical value, a high- resistance state appears at a lower temperature below the Curie temperature. And the appeared resistance peak at low temperature turns out to be extremely sensitive to a weak current. Even a very small current could greatly depress the height of the peak, an abnormal ER effect appears. Maximum resistance ratio ER, defined as [R(1 mu A)-R(100 mu A)]/R(100 mu A), is about 1257% at 50 K. Physics related to the appearance of the novel state and the abnormal ER effect is discussed. (C) 2014 AIP Publishing LLC.