Switching behavior of La_(1-x)Ca_xMnO_3 thin films grown on SrTiO_3 substrates

摘要

We report the switching behavior of resistive states induced by current flowing in La_(1-x)Ca_xMnO_3 films. The transport behavior upon treatments by applying a large dc current has been investigated in the absence of magnetic field. A switching from low to high resistive state was found upon applying a large dc current for the both compositions. The critical currents for the switching are 10.5 mA (density of 2.3 X 10~3 A/cm~2) and 6.7 mA (density of 1.6 X 10~3 A/cm~2) for compositions x=0.2 and 0.3, respectively. Our repeated measurements indicate that the high resistive state appeared in the film x=0.2 is much stable. Exposing the sample in air and room temperature does not cause any change of the transport properties. However, for the film with x=0.3, the induced high resistive state behaves with unstable characteristics. Keeping the sample at a low temperature of 20 K, a relaxation to a higher resistive state takes place. The mechanism of phase separation was taken into account in the interpretation of the observed phenomena.