Oxygen atmosphere-independent resistive switching effect at the CoCr2O4 (001) surface

Abstract

The resistive switching behavior of the spinel multiferroic CoCr2O4 film was investigated by in-situ scanning probe microscope in different atmosphere. The CoCr2O4 film on SrNbxTi1−xO3 substrate has an epitaxial structure and flat surface. Obvious local resistive switching along with reversible Fermi level shift were achieved by applying driving voltage with different polarity on the film surface, which suggests that the RS effect occurs uniformly near the top surface of the film. Unlike the oxygen ion migration related interface type RS effect, the CoCr2O4 film shows nearly identical RS behavior in both vacuum and oxygen rich atmosphere. Such oxygen atmosphere independent RS behavior was attributed to the charge trapping/detrapping process near the film surface. Furthermore, the stable RS effect with the same behavior was also found in macroscopic devices. These results demonstrate that the CoCr2O4 based RS devices have a robust switching performance and may have important applications in complex environment.