Ferroelectric Domain Controlled Pb[(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 ]O 3 Single Crystal with Giant Electromechanical Coupling Factor of k 31 Mode and Piezoelectric d 31 Constant

Temperature and poling field dependences of the properties of large high-quality piezoelectric single crystals of Pb[(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 ]O 3 (PZNT91/09) grown by the Bridgman method were measured. The single crystals poled along [001] of the original cubic direction possess giant electromechanical coupling factor k 31 over 80% and piezoelectric d 31 constant nearly m 1700 pC/N. These giant k 31 and d 31 constants results from the control of ferroelectric domain configuration. PZNT91/09 multi-domain single crystal became single-domain in the directions parallel and perpendicular to the poling field resulting in the appearance of giant k 31 and d 31 .