Magnetic and orbital structures of manganites in the electron doping region

Total energies of various magnetic and orbital configurations of the La1 - yCayMnO3 manganites were calculated for the electron doping region y > 0.5 with inclusion of the manganese e(g) level splitting. The state of the system was first established by total energy minimization in both the angle between the spins of neighboring Mn4+ ions and the two orbital-mixing angles defining the type of ordering in the system under study. The manganite phase diagrams constructed for T = 0 correctly reproduce the alternation of magnetic orbitally ordered structures, which is experimentally observed to occur with increasing electron concentration in the region of actual values of the Heisenberg interatomic exchange parameter, the Hund exchange parameter, and the hopping integral. (C) 2003 MAIK "Nauka / Interperiodica".