Structural, dielectric and vibrational properties of Ba(1−x)Bix[Ti0.95(Yb0.5Nb0.5)0.05](1−x)FexO3 ceramics (0≤x≤0.2)

Lead-free Ba(1−x)Bix[Ti0.95(Yb0.5Nb0.5)0.05](1−x)FexO3 (0≤x≤0.2) ceramics were prepared using the solid state reaction method. The effect of cationic substitution of Bismuth and iron in A and B sites, respectively, in BaTi0.95(Yb0.5Nb0.5)0.05O3 perovskite on structural and physical properties have been studied using X-ray diffraction, dielectric measurements and Raman spectroscopy techniques. X-ray diffraction analysis revealed that all the samples crystallized at room temperature in a pseudo-cubic Pm3m perovskite structure. Dielectric measurements indicated that the prepared compositions showed a transformation from a classical ferroelectric to relaxor behavior as the rate of substituted x increased. The substitution of Baruim by Bismuth in the A site and Ytterbium/Niobium/Titane by iron in the B site introduced an amelioration in dielectric properties, observed principally in the increasing of the dielectric permittivity maximum and in the decreasing of dielectric loss. Relaxor behavior was also noted to improve, with ΔTm=21 K for Ba0.95Bi0.05[Ti0.95(Yb0.5Nb0.5)0.05]0.95Fe0.05O3 at Tm=299 K near room temperature. Raman spectra were studied as a function of compositions and temperatures. The results correlated well with dielectric measurements and allowed for a deeper understanding of microstructural properties.