| || Ferroelectric Properties and Transmission Response of PZN-PT Single Crystals for Underwater Communication
Author : Bubesh Babu, J.;Madeswaran, G.;Dhanasekaran, R.;Trinath, K.;Rao, A. V. N. R.;Prasad, N. S.;Abisekaraj, I. R.
Source : Defence Science Journal ; Vol:57(1) ; 2007 ; pp 89-93
Subject : 66 Chemical Technology
Keywords : Crystal growth;Sonar;Piezoelectric coefficient;Transducer;Underwater communication;PZN-PT single crystal;Electromechanical coupling factor;Dielectric constant;Ferroelectric constant
Abstract : Single crystal of Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 (PZN-PT) at the composition of morphotropic phase boundary (MPB) shows a very high electromechanical coupling coefficient, piezoelectric coefficient, and dielectric constant compared to conventional PZT ceramics. These exceptional properties of these single crystals find enormous applications in medical ultrasound imaging and underwater communication (Sonar). The growth of PZN-PT single crystals has been carried out by bottom-supported flux Bridgman method. There are many growth issues to be addressed during the process of growth. The grown crystals are oriented and cut along <001> direction with the crystal dimension of 8 x 6 x 1.5 mm3 for further analysis. The oriented crystals were poled at a rate of 1 kV/mm. The poled crystals have been characterised for dielectric, strain and piezoelectric values. Further, the poled specimen were tested for transmitting response at various frequencies in acoustic test facility and the difficulties in their growth.