Redox-based memristive metal-oxide devices

In this chapter, we introduce the reversible, nonvolatile change in electrical resistance of transition metal oxide interfaces known as resistive switching. This effect occurs driven by the application of external voltage stimuli and can be ascribed to electrically induced redox-processes, which occur either in a single, spatially confined switching filament, in multiple filaments or in a spatially homogeneous, area-dependent manner. In most cases, the redox-process in the metal-oxide goes along with a change in the valence state of the metal ion modifying the Schottky barrier at the oxide/electrode interface. We will first summarize the most important aspects of defects and solid state chemical reactions in oxides as well as their electronic transport properties, followed by an overview of the experiments and simulations which shaped the current knowledge about microscopic mechanisms driving filamentary and area-dependent resistive switching. After a discussion about the switching kinetics, the chapter will be concluded with a brief overview about the fields of applications as resistive random access memories for data storage or in neuromorphic circuits.