Structural characterizations and dielectric, magnetic, and optical properties of Ba2FeVO6 double perovskite ceramics

Here, we present the structural characterization and physical properties of Ba2FeVO6 (BFVO) ceramics prepared by the solid-state ceramic method, which is regarded as potential Mott multiferroics. Structural studies demonstrate that the BFVO ceramic samples crystallize in a hexagonal structure with R3c symmetry. SEM images show a spherical morphology of the ceramic grains with an average composition of Bi:Fe:V close to 2.0:1.0:1.0 determined by x-ray energy dispersive spectroscopy. Infrared spectra revealed the vibrational modes of [FeO6] and [VO6] octahedrons in the ceramics, and XPS spectra confirmed the dual chemical valence states of iron (Fe2+ and Fe3+) and vanadium (V3+ and V4+) and two states of oxygen species in the BFVO ceramics, while barium was present as Ba2+. The BFVO ceramics exhibit relaxor-like dielectric behavior with an activation energy of 0.62 eV. The antiferromagnetic (AFM) nature was confirmed in the BFVO ceramics, whereas a weak magnetism was observed at 2 K. The temperature dependence of magnetizations measured with (and without) field cooling across 2 K–300 K under external magnetic fields indicates the spin glass characteristics in the present system. A strong variation of the dielectric behavior observed close to the AFM transition temperature was due to the induced dielectric polarization via the magnetostrictive effect driven by AFM transition. The bandgaps (Eg) of the investigated ceramic samples were deduced from their UV–visible spectra. The Eg values were about 1.15 eV and 1.50 eV, which were ascribed to the d–d electronic transitions of Fe 3d t2g → Fe 3d eg and 6A1g → 4T1g, respectively.