Piezoelectric property and strain behavior of Pb (Yb _0.5 Nb _0.5) O ₃- PbHfO ₃- PbTiO ₃ polycrystalline ceramics

(1-x)Pb(Hf_1-yTi_y)O₃-xPb(Yb _0.5Nb_0.5)O₃ (x = 0.10-0.44, y = 0.55-0.80) ceramics were fabricated. The morphotropic phase boundary (MPB) of the ternary system was determined by X-ray powder diffraction. The optimum dielectric and piezoelectric properties were achieved in 0.8Pb(Hf_0.4Ti _0.6)O₃-0.2Pb(Yb_0.5Nb_0.5)O ₃ ceramics with MPB composition, where the dielectric permittivity ε_r, piezoelectric coefficient d₃₃, planar electromechanical coupling k_p, and Curie temperature T_c were found to be on the order of 1930,480 pC/N, 62%, and 360°C, respectively. The unipolar strain behavior was evaluated as a function of applied electric field up to 50 kV/cm to investigate the strain nonlinearity and domain wall motion under large drive field, where the high field piezoelectric d₃₃* was found to be 620 pm/V for 0.82Pb(Hf _0.4Ti_0.6)O₃-0.18Pb(Yb_0.5Nb _0.5)O₃. In addition, Rayleigh analysis was carried out to study the extrinsic contribution, where the value was found to be in the range 2%-18%.