Electric-field-tuned metallic fraction and dynamic percolation in a charge-ordered manganite

Abstract

A percolative insulator-metal transition triggered by strong electric field is observed in epitaxial thin films of (Pr_0.65La_0.35)_0.7Ca_0.3MnO₃. The field-driven metallic state is achieved in a regime of temperatures where the material is weakly ferromagnetic. Our experiments suggest that the metallic fraction reaches percolation threshold p_c at a field-dependent temperature T_pc. A strong frequency dependence of complex ac resistance in the vicinity of T_pc is consistent with the picture of percolative transport in a phase-separated medium.