Electronic transport properties and simulation of random resistor network in granular mixture system of La0.7Ca0.3MnO3 and CeO 2

Granular mixture samples were prepared with La0.7Ca0.3MnO 3(synthesized by solid reaction) and CeO2 mixed, pressed and sintered under different conditions. In resistivity versus temperature R(T) measurements, a metal-insulator transition was observed. R(T) data demonstrated that the sintering condition had a strong influence on the properties of the samples. A low sintering temperature had influence on the growth of small granules and their boundaries,a high-temperature and long-time sintering resulted in the formation of large granules. A random resistor network (RRN) model with a new iterative average method was used to simulate the transport property of the mixture samples. The simulation and experimental result in agreement. The result indicates that the RRN model is reasonable for understanding the electronic transport of the granular mixture samples consisting of La0.7Ca0.3MnO3 an d CeO2