Effect of carrier trapping on the hysteretic current-voltage characteristics in Ag/La0.7Ca0.3MnO3/Pt heterostructures

The current-voltage (I-V) characteristics and resistance switching mechanism of Ag/La0.7Ca0.3MnO3(LCMO)/Pt sandwiched films, which were deposited on Pt/Ti/SiO2/Si substrates by pulse laser deposition, were investigated. The I-V characteristics can be explained by hole carrier injected space charge limited (SCL) conduction controlled by Ag/LCMO interface traps exponentially distributed in energy. The hysteresis and asymmetry in the I-V curves are due to trapping/detrapping process of hole carriers. The resistance changes under different voltage range are related to the carrier trapping levels induced by the positive voltage bias. Retention property of resistance is attributed to ordering/disordering transition, which is discussed on the basis of trap-assisted interface phase separation scenario. Therefore, the resistance switching induced by voltage pulses is attributed to the interface induced bulklike limited transport effect.