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.
Categories: cond-mat.mtrl-sci cond-mat.str-el