Abstract
Ferroelectric Pb~0.982–z~La~0.012~Δ~0.006~Ba__~z~__(Zr~0.55~Ti~0.45~)O~3~ (PLZT; z = 0–6 mol%) ceramic compositions were fabricated by a mixed‐oxide method. X‐ray diffraction studies of sintered ceramics indicate the coexistence of rhombohedral and tetragonal phases in the 5 mol% Ba‐doped PLZT composition. Grain growth is inhibited with increasing Ba concentration in the PLZT system as evidenced by scanning electron micrographs. Dielectric constant and dielectric loss as a function of temperature suggest that ϵ~rt~ and tan δ are increased up to compositions containing 4 and 5 mol% Ba, respectively. The dielectric maximum (ϵ~Tc~) decreased to 4 mol% Ba and gradually increased to 6 mol% Ba, whereas, with increasing Ba concentration in the PLZT system, the Curie temperature (T~C~) decreased from the composition with no Ba to that with 6 mol% Ba. Relaxor behavior as a function of temperature and frequency was studied over the composition series. As the Ba concentration increased, the coercive field (E~c~) showed a gradual enhancement. Remanent (P~r~) and spontaneous (P~s~) polarizations decreased to the 5 mol% Ba composition. Piezoelectric charge coefficient (d~33~), piezoelectric planar coupling coefficient (k~p~) and piezoelectric thickness coupling coefficient (k~t~) increased to the 4 mol% Ba composition, which are potential compositions for sensor and actuator applications. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)