Spin, charge, and orbital ordering in the B-site diluted manganates La2-xSrxGaMnO6

Oxidation of the ferromagnetic B-site diluted manganese(III) perovskite La2GaMnO6 is investigated by synthesis of the La2-xSrxGaMnO6 series. At the x = 0.3 composition, which corresponds to diamagnetic element substitution at the B-site of metallic La0.7Sr0.3MnO3, the Mn-III and Mn-IV valences order in real space at low temperature with an unusual lamellar motif. Orbital ordering at the Mn-III centers in this array maintains ferromagnetism and enhances the static coherent Jahn-Teller distortion over that found for the pure Mn-III end-member, facilitating e(g) electron hopping in the insulating state. Further oxidation to x = 0.5 completely suppresses the charge and orbital ordering, leading to glassy rather than long-range ordered magnetism.