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.