Epitaxial thin films of layered double perovskite La2CuSnO6 were fabricated on (001)-oriented SrTiO3, (LaAlO3)(0.3)-(SrAl0.5Ta0.5O3)(0.7), and LaAlO3 substrates with a pulsed laser deposition method. B-site cation ordering of the layer structure can be controlled by tuning the substrate temperature during deposition. X-ray diffraction and scanning transmission electron microscopy revealed that the lattice parameters were strongly correlated with the degree of Cu/Sn ordering. The relationship between the lattice parameters and the B-site cation ordering originates in the orientation of the Jahn-Teller distorted CuO6 octahedra. (c) 2006 American Institute of Physics.