Lithium Substitution in LaMnO3: Synthesis, Structure, and Properties of LaMn1-xLixO3 Perovskites

LaMn1-xLixO3 perovskites have been synthesized by a flux method using LiCl. Substitution of Li+ creates mixed-valent manganese according to the formula LaMn3+1-3xMn4+2xLi+xO3, for 0.10,x,0.20. At low values of x, additional vacancies are found on the perovskite A and B sites. All the members crystallize in the rhombohedral (R-3c) perovskite structure and are semiconducting with no long-range magnetic order. The samples show spin-glass-like short-range magnetic correlations at low temperatures and Curie–Weiss behavior above ca. 150 K. The x=0.05 and 0.10 samples show a magnetoresistive effect of ~90% at 50 K and 8.5 T. The effect of Li+ substitution in LaMnO3 cannot be explained on the basis of a simple percolation model.