Modified Pb(Yb,Nb)O3–PbZrO3–PbTiO3 ternary system for high temperature applications

Ternary 33Pb(Yb1/2Nb1/2)O–(67−x)PbZrO3–xPbTiO3 [PYNZ–PTx] were investigated as a function of the PT contents. The maximum value of piezoelectric coefficient (d33) was obtained, being on the order of 540 pm/V with high Curie temperature (Tc) of 375 °C for PYNZ–PT48 composition being regarded as the morphotropic phase boundary (MPB). To further increase its properties, La2O3 with 0.0 mol% ≤ x ≤ 3.0 mol% was substituted for PbO as an A-site in ternary PYNZ–PT48 [PYNZT]. The substitution of La3+ for Pb2+ in PYNZT was found to increase the tetragonality, but greatly reduced Tc and broadened the dielectric permittivity maximum. The relative permittivity was found to follow a Curie–Weiss Law above the deviation temperature (TD). The optimized properties with d33 of 600 pm/V, maximum dielectric permittivity (ɛmax) of 22500 (at the Tc = 315 °C and 1 kHz) were obtained in PYNZT-La2.0.