Cation-ordering effects in the single layered manganite La{sub 2/3}Sr{sub 4/3}MnO{sub 4}.

Epitaxial La{sub 1-x}Sr{sub x}MnO{sub 3} {center_dot} SrO (x = 1/3) films were synthesized as random alloys and cation-ordered analogs to probe how cation ordering affects the properties of a two dimensional manganite. The films show evidence for a spin glass like phase below 20 K and weak ferromagnetic ordering up to 130 K. There is a dramatic difference in magnetic anisotropy and the low temperature transport mechanism depending on the cation order, which is consistent with differences in Mn 3d orbital occupancies. This work indicates that cation ordering can significantly alter the Mn 3d orbital ground state in these correlated electron systems.