High-resolution X-ray study of specular and diffuse scattering from Ni/C multilayer upon annealing

A high-resolution X-ray diffraction study of specular and diffuse scattering from a Ni/C multilayer upon annealing was performed to examine its optical characteristics and the structural changes of interfacial roughness. The Ni/C multilayer was deposited by the laser ablation technique. The data obtained at the optimal annealing temperature (about 590 K), show a drastic improvement in the reflectivity of the first Bragg order by a factor of 2.4, up to 81%, without any worsening of X-ray optical characteristics and any changes of macroroughness. It supports our previous conclusion that annealing at the optimal temperature causes the spinodal decomposition of the interfacial range between the metal and carbon layers. Both the improvement of the sharpness of the boundaries and an increase of the X-ray optical contrast provide a gain in reflectivity.