Temperature dependent piezoelectric anisotropy in tetragonal 0.63Pb(Mg_1/3Nb_2/3)-0.37PbTiO₃ single crystal

In this work, we studied the temperature-dependent effective piezoelectric coefficient d 33∗ along the arbitrary direction of a tetragonal 0.63Pb(Mg_1/3Nb_2/3)-0.37PbTiO₃ single crystal. Results show that the crystal changes from a rotator ferroelectrics with the maximum d 33∗ occurring along the nonpolar direction to a extender type with maximum piezoelectricity along [001]_C. Two polymorphic phase transitions, orthorhombic-tetragonal and tetragonal-cubic, greatly influence the P_S dynamics, leading to the change of d 33∗ anisotropy with temperature. The [011]_C oriented crystals possess both improved piezoelectricity and high thermal stability, hence are the best choice for practical applications.