Magnetic and Transport Properties of La0.7-xPrxPb0.3 MnO3

[[abstract]]The substitution of Pr on the La site in La1−xPrxPb0.3MnO3 has been studied in order to probe into the physical mechanisms of colossal magnetoresistance (CMR) behavior. The magnetic order changes from a long-range order with x=0.0 to a short-range nature with x=0.7. The ferro-paramagnetic and metal-insulator transition temperature values decrease as Pr content increases. The highest MR ratio value is 16.9% for x=0.0 against 41.6% for x=0.7 in an applied field of . It is suggested that the mean ionic radius of the La-site ions may plays an important role on the CMR effect