Abstract :
The temperature dependence of the resistance of composite samples (1−x)La0.67Sr0.33MnO3+xYSZ with different YSZ doping level x was investigated at magnetic fields 0–3 T, where YSZ represents yttria-stabilized zirconia. Results show that the YSZ dopant does not only adjust the metal–insulator transition temperature, but also increases the magnetoresistance effect. With increase of YSZ doping level for the range of x<2%, the metal–insulator transition temperature values TP of the composites decrease, but TP increases with increase of x further for the range of x>2%. Meanwhile, in the YSZ-doped composites, a broad metal–insulator transition temperature region was found at zero and low magnetic field, which results in an obvious enhanced magnetoresistance in the temperature range 10–350 K. Specially, a larger magnetoresistance value was observed at room temperature at 3 T, which is encouraging with regard to the potential application of magnetoresistance materials.
