Abstract
Using the measured elastic constants of TiN and NbN single crystals with cubic symmetry, the effective elastic constants of single-crystal TiN/NbN superlattice films with tetragonal symmetry, namely c11c12c13c33c44and c66have been calculated for various thickness ratios of the layers. Using a line-focus acoustic microscope, measurements of surface acoustic waves (SAWs) have been carried out on single-crystal TiN/NbN superlattice films grown on the (001) plane of cubic crystal MgO substrates. The phase velocities measured as functions of the angle of propagation display the expected anisotropic nature of cubic crystals. Dispersion curves of SAWs propagating along the symmetry axes have been obtained by measuring wave velocities for various film thicknesses and frequencies. The SAW dispersion curves calculated from the effectiveelastic constants and the effective mass density of the superlattice films show very good agreement with experimental results. The results of this paper exhibit no anomalous dependence of the elastic constants on the superlattice period of TiN/NbN superlattices.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2248-2256 |
| Number of pages | 9 |
| Journal | Journal of Materials Research |
| Volume | 7 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 1992 |
Funding
The measurements were carried out with a line-focus lens provided by Tohoku University through the courtesy of Professor N. Chubachi and Professor J. Kushibiki. Helpful discussions with Dr. J. Kushibiki are also gratefully acknowledged. This work was carried out in the course of research sponsored by the Office of Naval Research under Contract N00014-89-J-1362 and the National Science Foundation under Contract No. DMR 8817418.
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering