Abstract
Composites of 0.99 La-0.7(CaxSr1-x)(0.3)MnO3/0.01SnO(2) (LCSMO/SnO2) (x = 0, 0.1, 0.2, 0.5, 0.7 and 1) were synthesized using solid-state reaction technique, and then characterized using the X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD and SEM observations show the LCSMO and SnO2 phases are separately distributed in the composites which indicate that there was no chemical interaction occurred during the sintering process. SnO2 is mainly distributed at the grain boundaries and surfaces of the matrix. The resistivity of the composites was measured in the range of 100-350 K by using physical properties measurement system (PPMS). The applied magnetic field is 0 T, 0.5 T and 1 T. Enhanced magnetoresistance (MR) within a wide temperature range was obtained. The observed variation of MR with varying Ca and Sr concentration has been qualitatively investigated. (C) 2010 Elsevier B. V. All rights reserved.