Impact of electric currents on the insulator-metal phase transition in epitaxial thin films of La1−xAxMnO3 (A = Sr, Ca, and Ba)

The influence of dc currents with a high current density on the transport properties of epitaxial La_1−xA_xMnO₃ (A = Sr, Ca, and Ba) thin films were studied. An application of a large current could lead to a remarkable reduction in the insulator-metal phase transition peak, demonstrating a significant electroresistance effect. After removing such currents the samples could completely return to its pristine state. Our experiments reveal that such an electroresistance should be a common feature for the perovskite manganites, rather than the results caused by the self-heating or self magnetic field. It may be ascribed to the two aspects: one is the strong interaction between carrier spins and localized spins in Mn ions, the other is the percolative mechanism of phase separation.