The bilateral nonlinear electromagnetic excitation of longitudinal ultrasound in a metal plate is investigated theoretically. We considered a plate placed in a magnetic field ${\mathbf{h}}_0$ parallel to its surfaces with the conditions for the anomalous skin effect satisfied. The sound generation is due to the deformation and induction mechanisms of the electron-phonon interaction. The mechanism of nonlinearity is magnetodynamic: it is related to the influence of the radio-wave magnetic field on conduction-electron dynamics. It is demonstrated that even in a massive sample the singularities of acoustic oscillations on the plate faces are determined principally by the sound excited directly in the skin layer and, also, by the multiple reflection of sound waves from the sample boundaries. As a result, the role of the deformation mechanism of interaction increases notably. In the case of developed nonlinearity the sound vibrations represent a very complex superposition of sharp jumps with series of sharp spikes. The number of spikes in a radio-wave period depends on the sound damping, and increases considerably when the damping decreases. Because of the formation of the standing sound wave in the metal, each harmonic has a spatial resonance. The evolution of the hysteresis of the sound field, as a function of the external field ${\mathit{h}}_0$, with increasing the amplitude of the exciting radio wave is studied.

• Received 7 May 1993

DOI:https://doi.org/10.1103/PhysRevB.48.9434