Colossoal magnetoresistance and large magnetic entropy change in La2/3Ca1/3Mn1-xSix O3 (x = 0.05–0.20) manganites

Abstract

Magnetotransport and magnetocaloric properties of polycrystalline La2/3Ca1/3Mn1-xSixO3 (x = 0.05, 0.10, 0.15 and 0.20) have been studied. The colossal magnetoresistance (CMR) effect and large magnetic entropy change (ΔSM) have been found in the vicinity of Curie temperature (TC). With the increases of Si content x, the MR and ΔSM peak positions as well as TC gradually shift to low temperatures, while MR peak value gradually increases from 84% to 140%, and the maximum value of magnetic entropy change remains nearly the same high value, in the range of 8.4 − 9.6 J Kg−1 K−1 for a magnetic field variation of 6 T.