We report a real-time observation of strain relaxation during in situ growth of SrTiO 3 thin films by measuring the in-plane lattice constant at the film surface using reflection high-energy electron diffraction. The initial misfit strain in the SrTiO 3 film is tensile on MgO and compressive on LaAlO 3 as expected from the lattice mismatches between the film and the substrates. Strain relaxation begins immediately after the deposition starts, but is not complete until the film thickness reaches 500-2500 Å depending on the substrate and the deposition temperature. The strain relaxation at the growth temperature influences the film strain at room temperature, which is compressive for both substrates for thin SrTiO 3 films.

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Point defects in annealed B2-phase FeAl samples in the range 47-53 at.% Fe were studied using 57Fe MSssbauer spectroscopy. Spectra were analyzed using local environment models according to which point defects in atomic shells close to probe atoms induce shifts in the nuclear monopole interaction. For well-annealed samples, better results were obtained assuming only the presence of Fe~ antisite and VFe vacancy defects, and not of AIFe antisite defects. Monopole interactions of 57Fe probes on the Fe and Al sublattices having no defects in the first two shells were about + 0.27 and -0.03 mms -1, respectively, with respect to Fe in alpha-Fe metal. The shifts induced by Fe~ and VFe defects in the first shells of Fe probes on the Fe and Al sublattices were -0.15 and -0.24 mm s -1, respectively, and, in the second shells, +0.06 and +0.011 mms -1. In addition to structural defects needed to accommodate deviations from stoichiometry, annealed samples were found to contain several percents of Fe~ and VFe defects due to lattice disorder, with greater disorder in Fe-deficient alloys.PACS 61.72.Cc -Kinetics of defect formation and annealing. PACS 61.66.Dk -Alloys. PACS 76.80 -M5ssbauer effect; other y-ray spectroscopy. PACS 01.30.Cc -Conference proceedings.

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