Attenuation measurements of an ultrasonic Rayleigh wave propagating along rough surfaces

The attenuation of Rayleigh surface waves by one- and two-dimensional rough surfaces is investigated on duraluminum and titanium samples. The root-mean-square deviation of the surface from flatness h (8.5<h<90 μm) satisfies the condition of validity of the perturbation theory approach ε=h/λR≪1. The excitation frequencies of the transmitter vary from 2.2. to 10 MHz. Experimental results for one- and two-dimensional rough surfaces are presented and discussed. A comparison with the theoretical calculations of Eguiluz and Maradudin [Phys. Rev. B 28, 728 (1983)] confirms the F5 dependence of the attenuation α as aq∥→0.