Concurrent resistive and capacitive switching of nanoscale TiO2 memristors

The interest on nanoscale resistive switching elements has recently shown a rapid increase owing to their potential for non-volatile memory applications, reconfigurable architectures and neuromorphic computing. In turn, this has rendered research on the physical switching mechanisms of distinct materials and architectures that facilitate memristive phenomena, with the most prominent mechanisms being the displacement of mobile ions, the formation and rupture of conductive filaments and the phase-transitions of an active core; a variety of models describing each scenario. In this paper we provide experimental evidence on a switching mechanism that depends upon the expansion/contraction of a TiO2 thin film that serves as the active core for a nanoscale memristor, due to a re-oxidation/de-oxidation (reduction of TiO2) process supported at the top TiO2/Pt interface of the device.