Asymmetric behavior of charge-orbital order in electron/hole-doped A-site ordered manganites Eu(Ba1-yLay)Mn2O6 and (Eu1-xCax)BaMn2O6

We have investigated the electron- and hole-doping effects on the charge-orbital order in the ordered-perovskite manganite, EuBaMn2O6. In the electron-doping case of Eu(Ba1-yLay)Mn2O6, the stacking manner of the commensurate charge-orbital ordered (CO-OO) sheets is variable between AABB and ABAB types, because of the competition between Jahn-Teller distortion and Coulomb interaction energies arising from Eu/Ba cation ordering. In the hole-doping case of (Eu1-xCax)BaMn2O6, on the other hand, the switching of the stacking pattern of the incommensurate CO-OO sheets does not occur, and the stacking pattern is perhaps identical with that of conventional solid-solution manganites (AAAA type).