Hysteretic magnetoresistance in Nd1-xSrxMnO3 films with controlled carrier density

Magnetotransport characteristics and their nominal hole concentration (x) dependence were investigated in Nd1-xSrxMnO3 films. Thermal hysteresis in resistivity indicating the occurrence of a first-order phase transition was observed for x = 0.35 and 0.50, but essentially not for x = 0.40 and 0.45. The x = 0.35 and 0.50 films also show hysteresis in magnetoresistance. Once the resistivity is decreased by an order of magnitude by application of a magnetic field, the low-resistivity state is maintained even after removal of the field below a critical temperature. Observed hysteretic behavior suggests the presence of instabilities which complete with double-exchange interaction in specific hole concentration regions, which may be one of the origins of the colossal magnetoresistance.