Electron diffraction evidence of charge-ordering at room-temperature in La 1− xCa xMnO 3 (0.55≤ x≤0.67)

Abstract

Temperature dependent electron diffraction of La 1− x Ca x MnO 3 for 0.55≤ x≤0.67 using transmission electron microscope (TEM) has been carried out in the temperature range of 106–300 K to study the melting of charge-ordering across the transition temperature. Clear signature of charge-ordering as evident by the presence of diffuse super-lattice spots persist even at room temperature. This has been consistently observed for four different samples with compositions within the range of 0.55≤ x≤0.67. The results indicate emergence of some degree of itinerancy in the localized charge carriers as temperature rises.