Colossal Magnetoresistance in Fine Particle of Layered-Perovskite La2—2xCa1+2xMn2O7 (x = 0.3) Synthesized at Low Temperatures

Abstract

By means of a sol–gel method, we prepare layered-perovskite samples of La2—2xCa1+2xMn2O7 (x = 0.3) at synthesis temperatures from 1000 to 1200 °C. The grain size changes from 20 to 45 nm. A magnetoresistance above 25% at low temperatures is acquired in a field of 0.8 T. We also find that decreasing grain size is determining for getting a larger magnetoresistance. These results may be beneficial to future application.