Line-focus acoustic microscopy measurements of Nb/sub 2/O/sub 5//MgO and BaTiO/sub 3//LaAlO/sub 3/ thin-film/substrate configurations

Abstract

Line-focus acoustic microscopy has been used to measure the phase velocities of surface acoustic waves on bare MgO and bare LaAlO/sub 3/, and on Nb/sub 2/O/sub 5//MgO and BaTiO/sub 3//LaAlO/sub 3/ thin-film/substrate configurations. The thin films are polycrystalline materials. The substrates are anisotropic single-crystals. The measured angular variation of the surface acoustic wave velocities has been used to determine the elastic constants of MgO substrate and Nb/sub 2/O/sub 5/ thin-film. It has been assumed that the Nb/sub 2/O/sub 5/ films may be considered as essentially isotropic. The measurements for LaAlO/sub 3/ and BaTiO/sub 3//LaAlO/sub 3/ show anomalies which are attributed to twinning in the LaAlO/sub 3/ substrate.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>