Sol-gel epitaxial growth of La1-xCaxMnO3 with colossal magnetoresistance effect

The successful sol-gel growth of colossal magnetoresistive La-Ca-Mn-O powder and epitaxial thin film is reported. Homogeneous powders were prepared at a temperature of 315 degrees C and epitaxial thin films were obtained on MgO(100) and LaAlO3(100) through heat treatment at 700-950 degrees C. A transition from semiconductor (negative d rho/dT) to metal (positive d rho/dT) was observed at 225 K, which was located in proximity to the magnetic transition temperature (T-c) of 228 K. A peak magnetoresistance ratio of similar to 900% occurred at 220 K. (C) 1996 American Institute of Physics.