Ce-doped LCMO CMR manganites: a consequence of enhanced T c and T IM

Abstract

A series of Ce-doped (1–20 mol%) La0·67Ca0·33MnO3 (LCMO) sintered (1400°C) ceramic samples were prepared by the solid-state reaction route. The significant enhancement of metal insulator transition temperature (T IM ≈ 280 K) and Curie transition temperature (T c ≈ 270 K) associated with LCMO system by the addition of 10 mol% of Ce has been observed. Further interesting observation showed that both low (≈ 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 ≈ 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.