Estimation of Nonlinear Piezoelectricity of PNN-PT-PZ and PNN-PT Ceramics
K.Yamamoto (Institut d'Electronique et de Microelectronique du Nord (IEMN-DOAE, CNRS 8520), Ecole Centrale de Lille, Villeneuve d'Ascq, France); A.Kokubo, K.Sakai, K.Takagi (Institute of Industrial Science, University of Tokyo, Tokyo, Japan)
The 3rd-order nonlinear piezoelectric constants of relaxor-type perovskites ceramics, 50PNN-35PT-15PZ and 64PNN-36PT, were estimated by dynamic measuring of velocity variation under alternating electric field. Their nonlinearity was much larger than the current lead zirconate titanate (PZT) ceramics of different types. We have succeed in the generation of acoustic phase conjugate waves through the nonlinear properties of PZT ceramics and obtained the efficiency over 100%, the efficiency being defined as the intensity ratio of the phase conjugate wave to the incident wave. We 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 very large values that could make a phase conjugator with 300% to 500% efficiency.
Section : 10