Structural, optical and conductivity properties in tetragonal BaTi 1- x Co x O 3 (0≤ x ≤0.1).

This work investigates the structure, optical and electrical conductivity properties of BaTi 1- x Co x O 3 (0≤ x ≤0.1) ceramics prepared by the hydrothermal method. The X-ray diffraction and Raman scattering analysis demonstrates that the prepared samples have a single-phase tetragonal structure with P 4 mm symmetry. The UV-vis diffuse reflectance spectrum confirms the influence of Co concentration on the direct optical band gap of BaTi 1- x Co x O 3 ceramics. The optical band gap shifts from 3.14 eV to 3.44 eV as the Co concentration increases from 0 to 0.1. The dielectric constant increases with the depletion of frequency according to the Maxwell-Wagner and Koops model. The AC conductivity versus frequency curve indicates that the conduction mechanism is determined by using the correlated barrier hopping (CBH) model. The Cole-Cole plot of the complex impedance was investigated for the prepared samples. The compounds showed dielectric relaxation of the non-Debye type.