Enhanced magnetoresistance of La2/3Ca1/3MnO3/CeO2 nanocystalline composites synthesized by polymer-network gel method

摘要

Using a dispersing particle polymer-network gel method, we prepared xLa(2/3)Ca(1/3)MnO(3)/(1-x)CeO2 nanocystalline composites, where the average grain sizes of La2/3Ca1/3MnO3 and CeO2 are about 30 nm and less than 10 nm, respectively. The magnetoresistance of the sintered composites is explored as a function of the ratio of metal/insulator, temperature, and magnetic field. The system exhibits metallic percolation threshold at x=x(p)similar to 35, around which the high field magnetoresistance has a maximum (similar to 70) at 50 K and 5 T, and the low field magnetoresistance value is close to 16 at 5 K and 0.05 T. (c) 2007 American Institute of Physics.