Structural, morphological, dielectric and optical properties of double perovskites RBaFeTiO (R = La, Eu).

Double perovskites RBaFeTiO (R = La, Eu) were successfully synthesized using a solid state reaction route. Structural refinement analysis has been performed to investigate the details of the crystalline structure which was found to be a cubic double perovskite structure at room temperature (space group 3̄, No. 221). Crystallite size, lattice strain, density, and porosity parameters were also calculated. The morphology and the elemental composition were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and elemental mapping. FTIR and Raman scattering spectroscopy have been performed in order to study the vibrational modes and the various bond formations of the synthesized samples. The optical properties investigated by means of the optical absorbance measurements highlight that both materials present large band gap energies, and are thus potential candidates for various technological applications. The electrical behavior of these double perovskites was also studied by frequency-dependent dielectric measurements and impedance spectroscopy. The electrical conduction follows Jonscher's power law and the conduction mechanisms are identified.