Chemical pressure effect on CMR behavior of Sr substituted La0.67Ca0.33-xSrxMnO3

A series of systematic substitution of isovalent Sr ion into the Ca site of La0.67Ca0.33-xSrxMnO3 system has been studied for different x values ranging from x = 0.00, 0.033, 0.066,..., 0.33. It is observed that at x = 0.066, the system begins to exhibit multiphasic behavior with the onset of X-ray shoulder peak at 20 value of 32.96 degrees. In this paper, we report low field SQUID magnetization behavior and electrotransport properties of the above system with x = 0.00, 0.033 and 0.066. It is noted that larger cationic size (Sr 21) does not allow the system to attain low bandwidth, which is the important parameter to control the electric and magnetic properties including Curie temperature (T-c) and metal insulator transition temperature (T-IM). The role of Sr 21 ion substitution as larger radius with respect to Ca 21 ion in the La0.67Ca0.33-xSrxMnO3 system can specifically be assigned to enhance the electron bandwidth (W), which promotes higher T, and T-IM. In addition to this, an interesting spin glass cluster and transition phenomena are observed at low temperature region (approximate to 50 K) for x = 0.066. (C) 2007 Elsevier B.V. All rights reserved.