ESTIMATION OF NONLINEAR PIEZOELECTRICITY OF 0.5Pb(Ni1/3Nb2/3)O3-0.35PbTiO3-0.15PbZrO3 AND 0.64Pb(Ni1/3Nb2/3)O3-0.36PbTiO3 CERAMICS

The 3rd-order nonlinear piezoelectric constants of relaxor-type perovskite ceramics, 0.5Pb(Ni1/3Nb2/3)O3-0.35PbTiO3-0.15PbZrO3 (50PNN-35PT-15PZ) and 0.64Pb(Ni1/3Nb2/3)O3-0.36PbTiO3 (64PNN-36PT), were estimated by the dynamic measuring of velocity variation under an alternating electric field. Their nonlinearity was much larger than that of the various types of current PZT ceramics. Authors have succeeded in the generation of acoustic phase conjugate waves through the nonlinear properties of PZT ceramics and obtained an efficiency > 100%, the efficiency being defined as the intensity ratio of the phase conjugate wave to the incident wave. Authors theoretically calculated the phase conjugate efficiencies in both 50PNN-35PT-15PZ and 64PNN-36PT ceramics from the measured 3rd-order nonlinear piezoelectric constants and found large values that could yield a phase conjugator with 300% to 500% efficiency. 11 refs.