Electronic structure, optical and Mössbauer investigations of ferroelectric [Pb(Fe0.5Nb0.5)O3]0.2-[(Ca0.2Sr0.8)TiO3]0.8.

In this research article, we report the various functional properties of [Pb(Fe0.5Nb0.5)O3]0.2- [(Ca0.2Sr0.8)TiO3]0.8 perovskite ceramic compound prepared by the solid-state process. Rietveld refinement proved that the compound crystallises in a pseudocubic structure as the primary phase. The dual oxidation states of Fe, Nb, Ti and the presence of oxygen vacancies were analysed by X-ray photoelectron spectroscopy. Ti–O and Ti–O–Ti prominent perovskite vibrations were examined by Fourier transform infrared (FTIR) analysis. Raman spectroscopy technique was employed to study the asymmetric TiO6 octahedral stretching and A1g phonon mode of PbFe0.5Nb0.5O3 (PFN). Field emission scanning electron microscopy (FESEM) predicted better grain growth with an average grain size of 2.445 µm. Energy-dispersive X-ray spectroscopy (EDS) analysis was done for elemental confirmation and purity of the sample. A detailed optical analysis was done by incorporating both absorbance and diffuse reflectance spectroscopy. A narrow band gap was revealed from the optical studies and Urbach energy was analysed. The conduction band minimum (CBM) level was estimated to be − 1.14 eV exploring the photocatalytic response. Electrical properties were investigated in terms of dielectric constant, conductivity, complex impedance and modulus analyses. A weak ferroelectric response was noticed with the remnant polarisation of 0.181 µC / cm2 from P–E loop analysis. Mössbauer spectroscopy revealed a strong paramagnetic doublet indicating the high-spin Fe3+ species in the octahedral environment. [ABSTRACT FROM AUTHOR]