  We have synthesized epitaxial La(1-x)Sr(1+x)MnO4 (x=1/3) films as random
alloys and cation-ordered analogues to probe how cation order affects the
properties of a 2D manganite. The films show weak ferromagnetic ordering up to
130 K, although there is a dramatic difference in magnetic anisotropy depending
on the cation order. While all films exhibit similar gapped insulator behavior
above 130 K, there is a significant difference in the low temperature transport
mechanism depending on the cation order. Differences in magnetic anisotropy and
low temperature transport are consistent with differences in Mn 3d orbital
occupancies. Together this work suggests that cation ordering can significantly
alter the Mn 3d orbital ground state in these correlated electron systems.
