A series of Ce-doped (1-20 mol%) La0.67Ca0.33MnO3 (LCMO) sintered (1400 degrees C) ceramic samples were prepared by the solid-state reaction route. The significant enhancement of metal insulator transition temperature (T-IM approximate to 280 K) and Curie transition temperature (T-c approximate to 270 K) associated with LCMO system by the addition of 10 mol% of Ce has been observed. Further interesting observation showed that both low (approximate to 1 mol%) and high (>= 15 and 20 mol%) level of Ce-doping in LCMO reduced the T-IM appreciably from 280 K to 220 K, and from 100 to 160 K, respectively exhibiting the signature of a unique spin glass transitions at around 30 K. Structural and spectroscopic studies revealed that unreacted CeO2 and MnO2 phases are found to be present in 1, 15, 20 mol% Ce-doped LCMO samples, which is one of the reasons why they show spin glass transition at low temperature. Our present results on bulk Ce-doped (10 mol%) LCMO are found to be encouraging as far as T-IM of epitaxial La0.7Ce0.3MnO3 thin film (T-IM approximate to 250 K) is concerned. This finding suggests that single-phase materials of Ce-doped (10 mol%) LCMO can be prepared with enhanced T-IM effectively using solid-state reaction route.
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