Piezoelectric Shear Coefficients of Pb(Zn_1/3Nb_2/3)O₃–PbTiO₃ Single Crystals

The piezoelectric and electromechanical properties of rhombohedral Pb(Zn_1/3Nb_2/3)O₃–PbTiO₃ (PZNT, PT<9%) single crystals in the shear mode are reported. PZNT8 single crystals poled along the <111> direction with electrodes on the (110) faces (X cut) were found to have the electromechanical coupling factor reaching 97% and piezoelectric coefficients around 9200 pC/N. The high level of piezoelectricity of the single crystals is related to the high dielectric permittivity, with values of 17000. The pure shear mode can be obtained by using a Y cut (electrodes on (112) faces) PZNT single crystal with suitable size ratio. The electrical properties were limited to about 60°C for PZNT8 single crystal, the breakdown of the single domain state to multi-domain state temperature, being expanded to ∼ 110°C for the PZNT4.5 composition.