Local structure and destruction of electron pathway effects on Curie temperature of B-site-substituted lanthanum manganites

A study of B-site-substituted La0.7Ca0.3Mn1−xScxO3 lanthanum manganites is presented. Substitution of Sc3+ ion for Mn3+ ion damages a path of motion of itinerant eg electrons, thus causing a weakening of double-exchange interaction and a decrease of Curie temperature, TC (about 35K for each 1% Sc doping from x=0 to 0.03). We suggest that the observed strong decrease of the TC with x is mostly caused by a difference in an electron configuration of the Mn3+ and Sc3+ ions and partially due to a change in the local parameters of the MnO6 octahedra because of the larger Sc3+ ion than the Mn3+ one. A method for distinguishing the effect of the above two factors on Curie temperature is supposed.