High-resolution x-ray diffraction studies of roughness and mosaic defects in epitaxial Fe/Au multilayers

The ability to distinguish between roughness and mosaic defect types in (00 1) and (111) oriented Fe/Au multilayers has been studied using synchrotron radiation. For the (001) orientation structures, the full-width at half-max imum of scans taken transverse to the 002 reciprocal lattice vector through the satellite diffraction peaks exhibit a parabolic dependence on the sate lite order which we interpret as arising from interfacial roughness. An add itional contribution, constant with satellite order, is identified with mos aic defects within the system. The observations are not fully consistent wi th an established theoretical defect model: the minimum in the parabolic fi t not occurring at the zero-order peak although the actual experimental min ima were found at this position. For the (111) oriented Fe/Au multilayers, no variation in the transverse width was found with satellite order. This w as attributed to the lower roughness, measured independently by grazing inc idence scattering.