Epitaxial Mo/NbN superlattices were grown on MgO(001) substrates by reactive dc magnetron sputtering. The epitaxial relationship between the bcc metal and the NaCl (B1)-structure compound is Mo(001) ∥NbN(001), Mo∥NbN, and the lattice mismatch is 1.4% given the 45° rotation about the (001). Cross-sectional transmission electron microscope images show well-defined and relatively planar layers. High angle x-ray diffraction results show up to 25 superlattice reflections extending over ≊30° in 2θ. Kinematical model fits to the x-ray diffraction data suggest that the interface widths were only ≊0.3 nm, presumably because of the immiscibility of Mo and NbN. Initial nanoindentation results indicate hardness values of ≊28 GPa, about 3 times the rule-of-mixtures value.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)