Unconventional piezoelectric coefficients in perovskite piezoelectric ceramics

Piezoelectric ceramics exhibit three conventional piezoelectric coefficients, i.e., d33, d31, d15, due to their ∞mm crystal symmetry. Unconventional piezoelectric coefficients, such as d11, d12, d13, d14, d16, etc., can only be extracted from piezoelectric single crystals of special symmetry with specific cut direction. Here we demonstrate a rotated poling method to realize unconventional piezoelectric coefficients in perovskite piezoelectric ceramics. This method is elaborated in theory and experimentally proven to be effective. Full nonzero piezoelectric coefficients in the 3 × 6 piezoelectric coefficients matrix can be obtained by combining these “quasi (effective) piezoelectric coefficients” with the conventional piezoelectric coefficients, which would expand applications in a wide variety of piezoelectric devices.