CHARGE ORDERING IN LOW-DOPING RATE A(1-X)B(X)MNO(3) (A-LA, PR B-SR, CA)

We have found charge ordering in perovskite-type manganese oxides at l ow-carrier-doping region in neutron diffraction experiments. In La1-xS rxMnO3 (x = 0.1 and 0.15), we observed superlattice reflections at com mensurate positions and the onset temperature T-p of the superlattice structure coincides with the low-temperature metal-to-insulator transi tion point. Pr1-xCaxMnO3 compounds are also studied at the stoichiomet ric concentration of x = 0.25. We observed diffuse satellite peaks ind icating the existence of new charge-ordered state at this concentratio n. (C) 1998 Elsevier Science B.V. All rights reserved.