Low-temperature magnetoresistance effect in the hydrothermally synthesized La0.98Ca0.02MnO3-δ/ γ-Mn2O3 granular system

The low-temperature magnetoresistance (LTMR) in hydrothermally synthesized La0.98Ca0.02MnO3-δ/ γ-Mn2O3 granular system was investigated. As-prepared powders are amorphous except for a small amount of crystalline phase LaCO3OH. After sintered at 1073 K or above, La0.98Ca0.02MnO3-δ perovskite and secondary phase γ-Mn2O3 coexist. A large LTMR of ∼65% at 127 K and ∼50% at 0 K in the sample with mean grain size of 23 nm was observed. The observation of a large magnetoresistance over a wide temperature interval could be of importance for useful applications.