Self-generated in-plane superlattice in relaxed epitaxial La0.67Sr0.33MnO3 films

The strain relaxation and its effect on the in-plane superlattice formation of epitaxial La0.67Sr0.33MnO3 (LSMO) thin films on the (LaAlO3)0.3(Sr2AlTaO6)0.7 (001) [LSAT (001)] substrates were investigated as a function of film thickness by x-ray diffraction. Rocking curves and reciprocal space mappings around (002) and (103) reflections reveal that the film with a thickness above 27nm is almost fully relaxed and has a modulated superlattice structure. The recovery of the pseudocubic angle of LSMO resulting from the relaxation of the shear strain introduced by the growth of rhombohedral LSMO on cubic LSAT was suggested to be the origin of the superlattice structure.