  We have studied the atomic ordering of B-site transition metals and magnetic
properties in the pulsed-laser deposited films of La2CrFeO6 (LCFO) and La2VMnO6
(LVMO), whose bulk materials are known to be single perovskites with random
distribution of the B-site cations. Despite similar ionic characters of
constituent transition metals in each compound, the maximum B-site order
attained was surprisingly high, ~90% for LCFO and ~80% for LVMO, suggesting a
significant role of epitaxial stabilization in the spontaneous ordering
process. Magnetization and valence state characterizations revealed that the
magnetic ground state of both compounds was coincidently ferrimagnetic with
saturation magnetization of ~2myuB per formula unit, unlike those predicted
theoretically. In addition, they were found to be insulating with optical band
gaps of 1.6 eV and 0.9 eV for LCFO and LVMO, respectively. Our results present
a wide opportunity to explore novel magnetic properties of binary
transition-metal perovskites upon epitaxial stabilization of the ordered phase.
