Dielectric and relaxor behavior of BaBi 4Ti 4O 15 ceramics

Abstract

Barium bismuth titanate BaBi 4Ti 4O 15 (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 °C) and frequencies (1.21 kHz–1 MHz). The broad dielectric constant peaks at temperature T m 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 E a = 0.013 eV, ν 0 = 2.09 × 10 8 Hz and T f = 651 K. All these parameters indicate that BaBi 4Ti 4O 15 is a relaxor ferroelectric. Ohmic conductivities and associated activation energies were evaluated using impedance spectroscopy.