Electric field driven dynamic percolation in electronically phase separated (La0.4Pr0.6)0.67Ca0.33MnO3 thin films

Competing ferromagnetic metallic (FMM) and insulating phases in the manganite (La1-yPry)(1-x)CaxMnO3 lead to a phase separated state in which micrometer scale FMM regions behave in a fluidlike manner over a narrow temperature range. Here we show that an electric field can realign the fluidlike FMM phases embedded in an insulating matrix, resulting in anisotropic in-plane resistance in microstructures of (La0.4Pr0.6)(0.67)Ca0.33MnO3 thin films. Time and voltage dependent resistance and magnetization measurements show that the dynamic percolation of the FMM regions leads to an insulator to metal transition due to electric-field induced realignment of the FMM regions, which is analogous to the dielectrophoresis of metallic particles suspended in fluid media. In-plane strain anisotropy plays an important role in determining the speed of dynamic percolation of the FMM regions by modifying the local electric fields in the phase separated state.