Investigation of surface leaky longitudinal waves on lithium niobate substrates

This paper focuses on studies of surface leaky longitudinal waves (SLLWs) on LiNbO₃ substrates. The theoretical results of searching SLLWs on LiNbO₃ in the range of Euler angles (0°, β, 90°) and (α, 0°, 0°) are presented, which shows the velocity can be up to 6700 to 7300 m/s nearly twice that of normal SAW and has attenuation in the order of 10^-6-10^-4 dB/λ, however very low piezoelectric coupling coefficient (no more than 0.14%) in the range of Euler angles (0°, β, 90°). The theoretical results also show that SLLWs, in the range of Euler angles (α, 0°, 0°) of LiNbO₃, have phase velocities 6500 to 7000 m/s and relatively high piezoelectric coupling coefficient (up to 0.6%). The experimental results at the Euler angles (0°, 38°, 90°) and (16°, 0°, 0°) on LiNbO₃ are also shown