Effect of Bi(B)O3 perovskite substitution on enhanced tetragonality and ferroelectric transition temperature in Pb(Zr,Ti)O3 ceramics

The structure, dielectric properties, and Curie temperatures of Pb(Zr1−xTix)O3 doped with 5 mol% Bi(Zn0.5Ti0.5)O3 (PZT–5BZT), 5 mol% BiFeO3 (PZT–5BF), and 5 mol% BiAlO3 (PZT–5BA) ceramics prepared by the conventional solid state reaction are reported. The structural phase transition temperature are compared with undoped and Bi(B)O3 doped Pb(Zr1−xTix)O3 ceramics for 0.48 < x ≤ 1 where B = Zn, Fe, and Al. A turning point was found around x = 0.70 where the Curie temperature (TC) of Bi(B)O3–PZT solid solution increases beyond that of pure PZT. Unlike most PZT-based ceramics, these systems show enhanced tetragonality. This effect is most dramatic in the PZT–5BF system, in which an extremely large c/a ratio of 1.057 is achieved for x = 0.90 sample, leading to the TC as high as 768 K.