Pure mode axis and the electromechanical coupling coefficients of the 0.67Pb(Mg_1/3Nb_2/3) O₃-0.33PbTiO₃ single crystal

Abstract

Pure mode axes of the 0.67Pb(Mg_1/3Nb_2/3)O₃-0.33PbTiO₃ (PMN-0.33PT) single crystals are investigated by slowness surfaces method. It is found only the Z-axis is a pure mode axis. The piezoelectricically stiffened Christoffel equation of the PMN-0.33PT crystal is solved in the rotating coordinate system. All of the single acoustic modes of thickness vibration are obtained. For the pure longitudinal mode of Z-cut crystal, the electromechanical coupling coefficient is up to 0.82. However, it is only 0.34 for the pure shear modes of X-cut or Y-cut crystal. It is along the pure mode axis that the maximum electromechanical coupling coefficients can be achieved.

KEYWORDS:

• PMN-0.33PT single crystal
• slowness surface
• pure mode axis
• electromechanical coupling coefficients

Additional information

Funding

The work was supported by the Natural Science Foundation of China (No. 61671199).