Reversible alternation between bipolar and unipolar resistive switching in polycrystalline barium strontium titanate thin films

The alternation from bipolar to unipolar resistive switching was observed in perovskite Ba0.7Sr0.3TiO3 thin films. By controlling the switching voltage, either bipolar or unipolar switching was obtained. When the switching voltage is higher than a threshold voltage, the device exhibits unipolar switching while if the switching voltage is lower than a threshold voltage, the device shows bipolar switching behavior. The bipolar-to-unipolar alternation is dynamically repeatable and may be related to the local modification of broken filaments by oxygen vacancy movement. (c) 2010 American Institute of Physics. [doi:10.1063/1.3369285]