P. Sonntag et al., GROWTH AND X-RAY CHARACTERIZATION OF THIN EPITAXIAL CR(110) FILMS ON NB(110), Physical review. B, Condensed matter, 49(4), 1994, pp. 2869-2874
We have grown by molecular-beam-epitaxy thin Cr(110) films on Nb(110)
buffer layers on sapphire Substrates. Films ranging from 50 Angstrom t
o 1100 Angstrom in thickness exhibit a single-domain structure. Using
extensive x-ray characterization methods, we find a pronounced in-plan
e expansion of the Cr layers which relaxes as the film thickness incre
ases, while the out-of-plane lattice spacing remains constant and bulk
like over the entire thickness range. The in-plane lattice relaxation
can be described by an isotropic strain relaxation model. In contrast,
the out-of-plane behavior is highly anomalous, which may be due to st
rain density waves.