Local structure and electron configuration effects on Curie temperature in La 0.7Ca 0.3Mn 1−xTi xO 3 lanthanum manganites

Abstract

X-ray diffraction, X-ray absorption near edge structure (XANES) and magnetization studies of La 0.7Ca 0.3Mn 1− x Ti x O 3 ( x=0, 0.05) manganites are presented. The substitution of Ti for Mn damaged a part of motion of itinerant e g electrons and changed the local parameters of perovskite cell causing a weakening of double-exchange interaction and a decrease in Curie temperature, T C, to about 103 K. According to XANES study, the Ti occupy the B(=Mn, Ti)-site in the tetravalent form. The cell parameters increased with x because the Ti 4+ ion is larger than the Mn 4+ ion.