Nonlinear current-voltage behavior and electrically driven phase transition in charge-frustrated LuFe₂O₄

¹  Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences - Beijing 100190, PRC
²  Department of Physics, Tsinghua University - Beijing 100084, PRC

Corresponding author: LJQ@aphy.iphy.ac.cn

Received: 18 September 2008
Accepted: 3 November 2008

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 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.