Dielectric and Piezoelectric Properties of Pb(Yb1/2Nb1/2)O3-PbTiO3 Solid Solution System

Solid solutions of (1- x)Pb(Yb1/2Nb1/2)O3-( x)PbTiO3 x=0 to 0.8 were investigated from the viewpoint of dielectric and piezoelectric properties. With increasing PbTiO3 content (x), phases at room temperature continuously changed from antiferroelectric (x=0), ferroelectric (x=0.1 to 0.15), relaxor (x=0.2 to 0.49), and again to ferroelectric (x>0.49), where crystal structures of all these phases were perovskite. Sintering temperature was lowered to around 950° C in the relaxor phase (x=0.2 to 0.49). Piezoelectric constants exhibited a maximum at x=0.49 to 0.50 near the morphotropic phase boundary (x=0.49). In the sample with x=0.50, Curie point was 349° C, and remanent polarization and coercive field were 32.8 µ C/cm2 and 2.75 kV/mm, respectively. Also, electromechanical coupling factors for planar (k p) and thickness (k t) modes were 0.527 and 0.436, respectively.