Dielectric Relaxation, Electrical Conductivity and Impedance Response of BaNb[sub 2]O[sub 6] Synthesized by Sol-Gel and Solid State Reaction Route: A Comparative Study

Abstract

BaNb2O6 (BN)—an important precursor material for the synthesis of lead free relaxors, is synthesized in the nano phase using a modified Sol‐Gel route in which the gel is formed by an aqueous solution of BaCl2, NbF5 and citric acid. The gel on decomposition at 700 °C yielded the nano phase of BaNb2O6 with particle size 48 nm. This is the lowest temperature for the formation of BaNb2O. Material is also prepared using the conventional solid state method in which the dominant columbite phase forms at 1100 °C after heating (6 h) with comparatively larger particle size of ∼1 μm. X‐ray diffraction analysis confirms that the BaNb2O6 prepared by both the methods stabilize in orthorhombic crystal structure. Dielectric relaxation is observed and the mechanism of relaxation is elucidated. Conducting charges and free charges both contribute to the dielectric relaxation in the materials. Electrical properties of the materials are studied using impedance spectroscopic technique. Detailed analysis of impedance spectrum suggests that the electrical properties are strongly temperature dependent. AC conduction activation energies are estimated from Arrheneus plots and conduction mechanism is discussed.