Elastic constants, Poisson ratios, and the elastic anisotropy of VN(001), (011), and (111) epitaxial layers grown by reactive magnetron sputter deposition

摘要: Elastic constants are determined for single-crystal stoichiometric NaCl-structure VN(001), VN(011), and VN(111) epitaxial layers grown by magnetically unbalanced reactive magnetron sputter deposition on 001-, 011-, 111-oriented MgO substrates at 430 °C. The relaxed lattice parameter ao = 0.4134 ± 0.0004 nm, obtained from high-resolution reciprocal space maps, the mass density ρ = 6.1 g/cm3, combination of Rutherford backscattering spectroscopy film thickness measurements, VN both in good agreement with reported values bulk crystals. Sub-picosecond ultrasonic optical pump/probe techniques used to generate detect longitudinal sound waves measured velocities v001 = 9.8 ± 0.3, v011 = 9.1 ± 0.3, v111 = 9.1 ± 0.3 km/s. c11 elastic constant is wave velocity measurements as 585 ± 30 GPa; c44 constant, 126 ± 3 GPa, surface acoustic measurements. From c11, c44, vhkl, ρ we obtain c12 178 ± 33 GPa, anisotropy A = 0.62, isotropic Poisson ratio ν = 0.29, anisotropic ratios ν001 = 0.23, ν011 = 0.30, ν111 = 0.29.