Structural, electrical, and multiferroic investigations of MgBiFeTiO6 double perovskite for possible optoelectronic applications

Abstract

Solid-state synthesis process with a higher thermal treatment of optimized sintering temperature of 1000 °C was utilized to develop the MgBiFeTiO₆ (MBFTO) orthorhombic (A21am) single-phase polycrystalline ceramic oxide. The initial investigation by the XRD method suggests an Aurivillius-type compound like A_m-1B_mO_3m, m = 5, while Rietveld analysis and tolerance factor (τ ~ 0.8) were also involved as an additional approximation tools to verify the structural formation. The SEM image confirmed a single-phase polycrystalline compound formation with av. grain size (~ 0.614 μm) is greater as compared to mean crystallites (~ 11 nm). The EDS spectra and elemental color mapping suggest the purity and uniform distribution of essential element over the surface of the sample. The ultraviolet–visible (UV–vis) absorbance spectra have a higher threshold wavelength (~ 630 nm) with a direct bandgap of ~ 2.36 eV suggesting better absorbance features in IR and visible radiation range, thus it can be utilized as a source material in photovoltaic and photocatalytic applications. The electrical and transport property was examined over 25–500 °C with a frequency sweeping 100–5 M Hz. The compound possesses an average ambient dielectric (~ 433) and low loss (~ 0.071) value at 1 kHz. The contribution of grains and grain barriers effect in semiconductance essence while an out of Debye-based relaxation mechanism that relies on the heat-dependent carrier mobility were verified as well. The material exhibited weak ferromagnetic behaviour and non-zero electric polarisation, with antiferromagnetic behaviour predominating. The outcomes of the examination suggest the present sample can be used in photocatalytic and dielectric material in suitable electronic equipments.