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Articles you may be interested inEffects of gas exposure on the surfaceacousticwave attenuation and magnetoresistance of nickel thin films J. Appl. Phys. 67, 4992 (1990); 10.1063/1.344700Magnetic field dependence of surface acoustic wave velocity and attenuation in nickel thin films Attenuation and phase velocity of surface acoustic waves interacting with charge carriers in thin metal films Appl. Phys. Lett. 33, 979 (1978); 10.1063/1.90259 Magneticfielddependent attenuation of surface waves by nickel thin filmsThe attenuation of Rayleigh-type waves traveling in a layered film-substrate combination is calculated by including a loss term due to viscous damping in the equation of motion for the film. The attenuation can thus be readily obtained without heuristic arguments by an analytic continuation of the analysis for the velocity of a surface wave without damping. Comparison to previous models is made for various film and substrate materials.

The temperature dependence of the ultrasonic attenuation of 700-MHz surface acoustic waves has been measured for nine films of superconducting NbN varying in thickness from 0.02 to 0.3 pm. The films, sputter deposited on LiNb03 substrates, exhibited attenuation changes in the superconducting state which were very similar in each case. These changes did not, however, follow the predictions of Bardeen, Cooper, and Schrieffer. Instead, they began with a sharp decrease for 1 or 2 dB at the transition temperature followed by a leveling off which remained nearly constant until T & 0.5 T, . It then decreased linearly with temperature until again leveling off below 1.5 K. A tentative explanation is proposed in terms of the Kosterlitz-Thouless vortex-antivortex theory.

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