The effect of La deficiency on structure and magnetic properties of La0.9-xSr0.1MnO3

A systematic study of the effect of La deficiency on structure, magnetic and electronic properties of ceramic samples of La0.9-xSr0.1MnO3 with a hole doping levels 0.01less than or equal toxless than or equal to0.05, was carried out. For a better homogeneity and stoichiometry, the ceramic samples were prepared by citrate synthesis and pyrolysis. X-ray investigations on these samples reveal that a rhombohedral structure was preserved on all La deficient samples. In addition to rhombohedral structure, an orthorhombic structure was observed for La deficient level of 0.02less than or equal toxless than or equal to0.04. We observed an evidence of an additional unknown structure for x = 0.05 La deficient level. All studied ceramics were found to be metallic below metal-insulator transition temperature with various magnetic phase transitions at different temperatures. These transitions were attributed to the existence of several crystal structures in these ceramic manganites. (C) 2004 Elsevier B.V. All rights reserved.