Hysteretic current-voltage characteristics and resistance switching at a   rectifying Ti/Pr$_{0.7}$Ca$_{0.3}$MnO$_{3}$ interface
  We have characterized the vertical transport properties of epitaxial layered structures composed of Pr$_{0.7}$Ca$_{0.3}$MnO$_{3}$ (PCMO) sandwiched between SrRuO$_{3}$ (SRO) bottom electrode and several kinds of top electrodes such as SRO, Pt, Au, Ag, and Ti. Among the layered structures, Ti/PCMO/SRO is distinct due to a rectifying current-voltage ($I$--$V$) characteristic with a large hysteresis. Corresponding to the hysteresis of the $I$--$V$ characteristics, the contact resistance of the Ti/PCMO interface reversibly switches between two stable states by applying pulsed voltage stress. We propose a model for the resistance switching at the Ti/PCMO interface, in which the width and/or height of a Schottky-like barrier are altered by trapped charge carriers in the interface states. 
A. Sawa, T. Fujii, M. Kawasaki, and Y. Tokura