Giant negative photoresistance of epitaxial manganite La2/3Ca1/3MnO3−δ film

The La 2/3 Ca 1/3 MnO 3− δ film has been deposited on the (001) SrTiO 3 substrate and its temperature-dependent photoconductive properties have been investigated from 80 to 300 K. The La 2/3 Ca 1/3 MnO 3− δ film has a novel photoelectric property due to its oxygen-deficient structure. We observed laser-induced giant negative photoresistance of the sample in a wide temperature range. The change rate of negative photoresistance was nearly 100% at the low temperature when the sample was irradiated by 532 nm laser. In addition, this effect was sensitive to the power of laser irradiation. The oxygen-deficiency of La 2/3 Ca 1/3 MnO 3− δ film seems to have an impact on the laser-induced resistance variation. The experimental results made the La 2/3 Ca 1/3 MnO 3− δ film a promising application as a photoswitch device.