Dielectric and relaxor behavior of BaBi4Ti4O15 ceramics

Barium bismuth titanate BaBi4Ti4O15 (BBiT) ceramics have been prepared using non-conventional solid-state reaction route based on mechanochemical synthesis during intensive milling. The X-ray diffraction method was used to determine phase composition. Dielectric properties were investigated in a wide range of temperatures (20-800 oC) and frequencies (1.21 kHz-1 MHz). The broad dielectric constant peaks at temperature Tm is frequently dependent. A modified Curie-Weiss relationship is used to study the diffuseness behavior of a ferroelectric phase transition where value of γ indicates the degree of diffuseness of barium bismuth titanate ceramics. The dielectric relaxation rate follows the Vogel-Fulcher relation with Ea = 0.013 eV, ν0 = 2.09 x 108 Hz and Tf = 651 K. All these parameters indicate that BaBi4Ti4O15 is a relaxor ferroelectric. Ohmic conductivities and associated activation energies were evaluated using impedance spectroscopy.