Transport characteristics in the first and second sweep cycles. (a) During the first sweep cycle, the voltage is swept in the forward direction until the device switches to high-resistance state. During the reverse sweep, the device remains in the high-resistance and shows hysteresis. (b) The device remains in the high-resistance state during the second sweep cycle and no hysteresis or switching is observed.
Umair et al. Nanoscale Research Letters 2013 8:476 doi:10.1186/1556-276X-8-476