Abstract
Electric transport measurements of the charge-frustrated LuFe2O4, in which charge ordering (CO) and electronic ferroelectricity are found, reveal a strong nonlinear electric conduction upon application of electric fields in both single-crystalline and polycrystalline samples. The threshold electric fields (Et) in LuFe2O4 are estimated to be about 60 V/cm and 10 V/cm with E parallel and perpendicular to the c-axis direction, respectively. Experimental measurements also demonstrate that the I-V nonlinearity increases quickly with decreasing temperature. Furthermore, our in situ TEM investigations clearly reveal that the nonlinear I-V behavior is intrinsically in correlation with a current-driven charge ordering insulator-metal transition, and the applied electrical field triggers a visible CO collapse recognizable as the fading of the satellite spots of the CO modulations.