  Ferroelectric memristors have attracted much attention as a type of
nonvolatile resistance switching memories in neuromorphic computing, image
recognition, and information storage. Their resistance switching mechanisms
have been studied several times in perovskite and complicated materials
systems. It was interpreted as the modulation of carrier transport by
polarization control over Schottky barriers. Here, we experimentally report the
isothermal resistive switching across a CoPt/MgZnO Schottky barrier using a
simple binary semiconductor. The crystal and texture properties showed
high-quality and single-crystal Co$_{0.30}$Pt$_{0.70}$/Mg$_{0.20}$Zn$_{0.80}$O
hetero-junctions. The resistive switching was examined by an electric-field
cooling method that exhibited a ferroelectric T$_C$ of MgZnO close to the bulk
value. The resistive switching across CoPt/MgZnO Schottky barrier was
accompanied by a change in the Schottky barrier height of 26.5 meV due to an
interfacial charge increase and/or orbital hybridization induced reversal of
MgZnO polarization. The magnitude of the reversed polarization was estimated to
be a reasonable value of 3.0 (8.25) $\mu$ C/cm$^2$ at 300 K (2 K). These
findings demonstrated the utilities of CoPt/MgZnO interface as a potential
candidate for ferroelectric memristors and can be extended to probe the
resistive switching of other hexagonal ferroelectric materials.
