X-ray scattering investigation of a SrTiO sub(3)(103) bicrystal interface

Synchrotron X-ray scattering has been employed to study the structure of a SrTiO sub(3)(103) bicrystal interface. The upper part of the bicrystal was thinned down to 25 mu m in order to allow the X-ray beam to penetrate down to the interface. The X-ray energy was set to 15.7 keV, just below the Sr K edge, to minimize absorption and further to enhance the penetration. No superstructures were detected along the tilt direction but, surprisingly, satellites were seen in the [010] direction perpendicular to the tilt direction in the neighbourhood of the (002) and (004) Bragg reflections. The spacing between the satellites was 0.02 reciprocal lattice units, which corresponds to a spacing of 195 angstroms along the interface. The satellites were sharp with a width corresponding to a correlation length in excess of 2600 angstroms. It is proposed that the satellites originate from sinusoidal modulations at the interface which arise from a 0.38 degree misalignment between the crystals and propagate from the interface deep into the bulk.