Realization of face-shear piezoelectric coefficient d36 in PZT ceramics via ferroelastic domain engineering

The piezoelectric face-shear (d36) mode may be the most useful shear mode in piezoelectrics, while currently this mode can only exist in single crystals of specific point groups and cut directions. Theoretically the d36 coefficient vanishes in piezoelectric ceramics because of its transversally isotropic symmetry . In this work, we modified the symmetry of poled PZT ceramics from transversally isotropic to orthogonal through ferroelastic domain switching by applying a high lateral stress along the "2" direction and holding the stress for several hours. After removing the compression, the piezoelectric coefficient d31 is found much larger than d32. Then by cutting the compressed sample along the zxt+45 deg direction, we realized d36 coefficients up to 206 pC/N which is measured by using a modified d33 meter. The obtained large d36 coefficients in PZT ceramics could be very promising for face-shear mode resonators and shear horizontal (SH) wave generation in nondestructive testing.