Nonlinear acoustic propagation in piezoelectric crystals

Nonlinear acoustic propagation of waves is examined, as it takes place from the easier to the more complex case, where surface acoustic waves propagate on piezoelectric substrates. The contribution of linear and nonlinear piezoelectric terms to the development of acoustic nonlinearities is qualitatively studied. Finally, experimental results of surface acoustic waves propagating on LiNbO3 crystals are presented, relative to peculiar effects produced in the nonlinear generation of new frequency waves.