Structural investigation and hyperfine interactions of BaBixLaxFe12−2xO19 (0.0≤x≤0.5) hexaferrites

Barium hexaferrite, BaFe12O19, substituted by Bi3+ and La3+ (BaBixLaxFe12−2xO19 where 0.0≤x≤0.5) were prepared by solid state synthesis route. The effect of substituted Bi3+ and La3+ ions on the structure, morphology, magnetic and cation distributions of barium hexaferrite were investigated by X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR) and Mössbauer spectroscopy. XRD powder patterns were refined by the Rietveld analysis method which confirmed the formation of single phase magneto-plumbite structure and the substitution of La3+ and Bi3+ ions into the lattice of barium ferrite. These results show that both La3+ and Bi3+ ions completely enter into barium hexaferrite lattice without disturbing the hexagonal ferrite structure. The EDX spectra confirmed the presence of all the constituents in expected elemental percentage. From 57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values on Bi and La substitutions have been determined. Cation distribution in the presently investigated hexaferrite system was estimated using the relative area of Mössbauer spectroscopy.