Coherent Interface Structures Observed in Co/Au(001) Epitaxial Superlattices

Abstract

A series of Co/Au(001) superlattices were prepared on GaAs(001) single-crystal substrates using an electron beam deposition method in an ultrahigh vacuum. X-ray diffraction spectra were measured with the scattering vector normal to the film surface, and diffraction peaks from the Co/Au(001) superlattices were observed throughout the entire measured range from low-angle to high-angle. For samples with noninteger numbers of atomic planes in one Co/Au bilayer unit, in the intermediate range (2θ: 20°∼31°) X-ray diffraction peaks indexed from the low angle side did not merge with those satellite peaks indexed from the Co/Au(002) fundamental peak in the high-angle range. This observation indicates a high crystalline quality for Co/Au(001) superlattices with a negligible fluctuation in layer thicknesses and a coherent interface structure.