Nonlinear absorption of longitudinal elastic waves in dislocationless crystals

Dissipative processes caused by nonlinear dependence of elastic wave absorption on the mechanical oscillation amplitude have been found in samples of dislocationless quartz. The appearance of elastic wave absorption in dislocationless crystals may be explained by energy losses generated by nonlinearity of connection between mechanical stresses and deformations in crystals if large-amplitude exciting stresses are applied. When deriving the formula for obtaining nonlinear absorption we used the system of elastic equilibrium equations, electrostatics and state equations. The results obtained testify to existence of lattice nonlinearity which explains the amplitude-dependent absorption of elastic waves in dislocationless crystals. Experimental data agree with the theory of nonlinear absorption of elastic waves in crystals.