Sintering characteristics and electrical properties of BaBi4Ti4O15 ferroelectric ceramics

Barium bismuth titanate (BaBi4Ti4O15) ceramics prepared by conventional solid-state reaction method have been characterized, and influence of sintering temperature is shown to greatly affect the electrical properties. Formation of a single phase composition with orthorhombic structure and a randomly oriented plate-like microstructure is confirmed. Raman spectroscopy reveals broad over-damped low frequency modes indicating structural disorder. Room temperature dielectric response in the low frequency range (10−2-10 Hz) reveals the influence of dc conductivity on dielectric dispersion. Analysis in terms of Lorentz type relation describes well the diffuseness in the dielectric data, and indicates only one polarization process in the system. The well fitting of frequency dependent maximum temperature (Tm) in ε′(T) to the non-linear Vogel-Fulcher equation and a similar trend in temperature dependent ac conductivity imply a relaxor-like nature of the material. Sintering at 1050 °C for 5 h is found to be favorable and yields ceramics with high density, high resistivity (4.6 × 1012 Ω cm), low dielectric loss (tan δ ∼ 0.05), remnant polarization (Pr = 3.63 μC/cm2) and a high piezoelectric charge coefficient, d33 = 24 pC/N.