Impact of metal silicide nanocrystals on the resistance ratio in resistive switching of epitaxial Fe3O4 films on Si substrates

Abstract

Fe3O4 films on Si substrates have been intensively studied for the realization of resistance random access memory composed of only ubiquitous elements. The biggest issue for the application of Fe3O4 film/Si in small-scaled devices is the low Off/On resistance ratio. For the enhancement of the Off/On resistance ratio, we propose epitaxial Fe3O4 films including hemispherical small metal α-FeSi2 nanocrystals on Si substrates, where an electric field is concentrated at the interface between Fe3O4/α-FeSi2. The concentrated electric field largely promotes the movement of oxygen ions, contributing to resistive switching. As a result, the Fe3O4 films including hemispherical small α-FeSi2 nanocrystals exhibit the largest Off/On resistance ratio (∼200) in Fe3O4-based nanomaterials. Finite element method simulations proved that the introduction of metal nanocrystals into films caused the enhancement of electric field intensity near the interface between nanocrystals and films. This significant enhancement method will open an avenue for realizing high-performance ubiquitous-element resistive switching materials in the next-generation information society.