Electric field-driven resistive switching in magneto resistive La0.5Ca0.5MnO3 thin films

In this work, the electrical behavior of polycrystalline La0.5Ca0.5MnO3 thin films, deposited by pulsed laser deposition (Pled) on Si3N4 buffered (1 0 0) Silicon substrate, is reported and discussed. Above a certain electric field value, a metal-insulating transition, at around 150 K, is found due to the appearance of connective paths with enhanced conductivity, activated by the electric field. The conductivity of the films is non-Ohmic and moderate electric fields result in resistivity switching to metastable low-resistive states. Positive and negative voltage pulses can switch the resistance of the film between a low (LR) and a high (HR) resistive state, if it is previously subjected to different cycling processes. A particular asymmetry in the electric current-voltage curve was also found. The hysteresis in one of the branches of the I-V curves shows that filamentary paths of increased conductivity induced by the electric field, are sensitive to the polarity of the applied voltage