Investigation of the structural, microstructural, optical and electrical properties of iron-doped barium titanate ceramics

The structural, microstructural, optical, and electrical properties of nanoceramic BaTi_1-xFe_xO_3-δ synthesized by sol--gel have been investigated. The X-ray diffraction analysis demonstrates that samples have a single-phase tetragonal structure with P4mm symmetry. This result was confirmed by the Rietveld method. Infrared spectroscopic analysis (FTIR) shows the presence of two bands at 490 Cm^-1 and 2358 Cm^-1 corresponding to T-O and C=O, respectively. On the other hand, scanning electron microscopy (SEM) results show that nanoceramics sintered at 1250°C have a spherical grain morphology. Grain size is small at X=0.02 and increases progressively thereafter. The UV--vis absorption spectrum confirms the influence of Fe concentration on the direct optical band gap of BaTi_1-xFe_xO_3-δ ceramics. The optical band gap shifts from 2.63 eV to 2.35 eV. Making this material a good candidate for solar photo-catalytic. There is an increase in Urbach energy as the Fe concentration increases from 0 to 0.4. On the other hand, the AC conductivity of the materials is subject to Joncher's law. The effect of Fe substitution concerns the decrease in conductivity at x=0.02 and then increases. The Cole--Cole complex impedance diagram was studied for the prepared samples. The compounds showed non-Debye-type dielectric relaxation, with a poor grain radius as Fe-doping increased.