Kinetics and relaxation of electroresistance in transition metal oxides: Model for resistive switching

Abstract

The kinetics of electric-field-induced resistive switching across metal ͑Ag͒-Pr 0.7 Ca 0.3 MnO 3 interfaces has been investigated. The resistance hysteresis ⌬R varies with the pulse amplitude V 0 roughly as a step function with existence of a threshold voltage V t for a fixed switching pulses width T w . On the other hand, the ⌬R varies with the pulse width ͑T w ͒ as a two-stage sequence at a fixed V 0 : an initial exponential rise with a time constant S Ϸ 2 ϫ 10 −7 s and a slow linearly increasing tail. The slow linear part is dominant only in the quasi-dc switch ͑pulse widthϳ a few seconds͒ below V t but negligibly small above it. The retentions of the ⌬R corresponding to the two stages are also extremely different, indicating that different underlying processes are involved. The relaxation time ͑ R ͒ is 10 8 s ͑ϳyear͒ or higher for the sub-s switching, in strong contrast with the total disappearance of the ⌬R after a few days for subthreshold ͑V 0 Ӷ V t ͒ quasi-dc switch. Different mechanisms, therefore, dominate the two different stages. More results obtained from time dependence study and impedance spectroscopy suggest that defect creation/annihilation, such as broken bonds under field, is likely the mechanism for the sub-s switching and that a slow accumulative process ͑like diffusion͒ of defects may be responsible for the subthreshold quasi-dc switch. Many observations further suggest that the accumulative process is much more complicated than simple migration/diffusion of the pre-existing defects.

Synergistic effects of electrical and optical excitations on TiO 2 resistive device

“…In contrast, the LRS conductance decreases rapidly, then decays slowly. Similar conductivity relaxation behaviors of the RS devices have been reported previously, [8,[28][29][30] although it has not been specified whether the measurements were performed in the dark. Nian et al have analyzed the conductivity relaxation in perovskite oxide film, and proposed an oxygen diffusion model with oxygen vacancy accumulating in the electrode interface region.…”

Study of defects in an electroresistive Au/La2/3Sr1/3MnO3/SrTiO3(001) heterostructure by positron annihilation

“…There has been a strong effort of the scientific community working to the development of the so called Oxide Electronics, essentially aiming to exploit the peculiar properties of oxides to extend the functionalities of conventional devices. High temperature superconductivity, 1 colossal magnetoresistance, 2 ferroelectricity, piezoelectricity, magneto-electric coupling, 3 optical activity, 4 and electroresistance 5 are only few examples of widely investigated phenomena exploited in prototypical devices (for a review see Ref. 6).…”

Interfacial resistive oxide switch induced by reversible modification of defect structures

“…From our observations, these partial switch states induced by subthreshold voltages are rather metastable and typically relax to a higher resistive value. As discussed elsewhere, 26 the two cases represent two different mechanisms, and electromigration plays important roles only in such subthreshold switching. Also, both the R ac value and the V p dependency vary broadly from sample to sample: V th as low as 1 V has been observed and ⌬R sometimes even appears as "multilevel switching" with V app .…”