Electrical resistance switching of YbFe₂O₄ single crystal bulk

We report the electrical resistance switching of YbFe2O4, which is one of the electronic ferroelectrics and shows multi-step polarization reversal. The electrical resistance of the single crystal bulk of YbFe2O4 was measured along the c-axis. Three kinds of resistance states were observed: high resistance state (HRS), low resistance state (LRS), and extra low resistance state (ELRS). The as-grown sample was in HRS. The resistance state switched from HRS to LRS under an electric field of similar to 180 V/cm. HRS was reproduced under the same magnitude of the electric field in the opposite direction. The switching from LRS to ELRS was assisted by a current flow in the ab-plane, which is orthogonal to the measurement axis (c-axis). The switching from LRS to ELRS was observed under an electric field of similar to 140 V/cm during the resistance measurement along the c-axis after a current flow in the ab-plane for a few seconds. The resistance ratio in HRS, LRS, and ELRS was similar to 2:1.5:1, which is regarded as a large value considering that the sample size was sub-millimeter order. This multi-step resistive switching is likely due to the multi-step reversal of electric polarization, accompanied by a multi-step change in Schottky barrier height between the sample and electrodes. The currents in the ab-plane are considered to release some pinnings and assist in the polarization reversal.