Phase transition in Sol-Gel processed barium titanate ceramics

Abstract

Ferroelectric barium titanate (BaTiO3) ceramics have been prepared from barium acetate [Ba(CH3COO)2] and titanium isopropoxide [Ti(CH3)2CHO)4] precursors by sol-gel technique The as-grown powder was found to be amorphous which crystallized to tetragonal phase after annealing at 700°C in air for one hour. The ceramics showed well saturated polarization-field (P-E) hysteresis loops at room temperature. The values of spontaneous polarization(Ps), remanent polarization (Pr) and coercive field (Ec) of the ceramics were found to be19.0, 12.66μC-cm−2 and 30KVcm−1 respectively. The room temperature dielectric constant (ε) and loss tangent (tanδ) of the ceramics were found to be 1135 and 0.012 respectively. The dielectric constant and tanδ showed anomaly peaks at 125°C showing ferroelectric to paraelectric phase transition. The polarization parameters also vanish at 125°C confirming the phase transition.