La1-xSrxMnO3-sigma(LSMO) thin films have been grown on SrTiO3 (0 0 1) single-crystal substrates using the laser molecular beam epitaxy (MBE) technique. The two-dimensional layer-by-layer growth was in-situ monitored by reflection high-energy electron diffraction (RHEED). Kinetic growth with surface relaxation was also observed, and crystallinity of the thin films was investigated by high-resolution X-ray diffraction. Results of 2 theta-omega scans revealed a strong correlation between out-of-plane lattice constant and oxygen content as well as strontium doping concentration. However, further analysis of rocking curve measurements around (0 0 2) plane of thin films grown under different oxygen pressure (P-O2) shown the effects of oxygen content on the crystal structure. An exceptionally low full-width at half-maximum (FWHM) of 0.02 degrees was measured from the sample grown at P-O2 of 5.0 Pa, indicating the almost perfect epitaxial growth of LSMO thin films. (C) 2009 Published by Elsevier B.V.