Tuning of colossal magnetoresistance via grain size change in La0.67Ca0.33MnO3

Abstract
In this article, we show how colossal magnetoresistanceeffect(CMR) can be tuned in polycrystalline mixed valence manganite La 0.67 Ca 0.33 MnO 3 via changing grain size by means of a sol-gel method. Below a critical diameter (150 nm), CMR disappears, but large intergrain MR remains even well above T c (1.2T c for ≈95 nm particles). Possible explanation for this effect involves single magnetic domain behavior in samples annealed at low temperature.