Coexistence of Filamentary and Homogeneous Resistive Switching in Fe‐Doped SrTiO₃ Thin‐Film Memristive Devices

Abstract

Conductive atomic force microscopy combined with a delamination technique is used to remove the top electrode of Fe‐doped SrTiO3 metal–insulator–metal structures and gain insight into the active switching interface. Both a filamentary and an area‐dependent switching process with opposite switching polarities are found in the same sample.

Probing the oxygen vacancy distribution in resistive switching Fe-SrTiO3 metal-insulator-metal-structures by micro-x ray absorption near-edge structure

“…Local conductivity investigations on Fe-doped SrTiO 3 MIM structures show an increase of conductivity localized to $ 1 lm, while the remaining area under the electrode remains highly insulating. 11 The presented lXANES study demonstrates that, during electroforming, the field-induced migration of oxygen vacancies is initially homogeneous over most of the electrode area, until electrical breakdown is achieved at a single point under the electrode. Figure 3(c) combines the conclusions of both experiments in a schematic sketch of the oxygen vacancy distribution in the memristor.…”

“…After the initially insulating devices are electroformed with a DC voltage of þ7 V (voltage bias applied to the Pt top-electrode), the MIM structures are switching in a "counter-eightwise" polarity, 11 as depicted in Fig. 1.…”

TinO2n−1Magnéli phases studied using density functional theory

“…This in turn can be changed (write operation) and measured (read) when subjected to an electric field. The insulator layer is a nanometer-thick thin film, which can be composed of a wide variety of materials, such as binary oxides [8], perovskites [9][10][11][12], as well as many other compounds, which are known for their resistance switching properties [13,14].…”

Anomalous effect due to oxygen vacancy accumulation below the electrode in bipolar resistance switching Pt/Nb:SrTiO3 cells

“…However, confusion arises because of several reports of the coexistence of both cf8-and f8-type curves in one sample. 13,14 To overcome these difficulties, a couple of explanations based on the homogeneity of V o¨d istribution in Fe-doped SrTiO 3 cells 13 and the position change of active Schottky interface in Pt/TiO 2 /Pt cells 14 were proposed. However, these models may be applicable to the specific BRS material systems.…”

“…15 The hopping barrier height U o is assumed to be 1.01 eV. 4,13,14 Then, ρ d (x) becomes changed over time due to the hopping motion of V o¨w ith p +a (x) and p −a (x), which are hopping probabilities for moving from x to x + a and x -a, respectively. In order to make a more realistic model, we took into account of non-uniform electric field due to Schottky barrier in the hopping motion, which were not considered in our earlier model.…”