Ferroelectric relaxor behavior and dielectric spectroscopic study of 0.99(Bi0.5Na0.5TiO3)-0.01(SrNb2O6) solid solution

0.99(Bi0.5Na0.5TiO3)-0.01(SrNb2O6) was prepared by simple solid state reaction route. Material stabilized in rhombohedral perovskite phase with lattice constants a = 3.9060 angstrom, alpha = 89.86 degrees and a(h) = 5.4852 angstrom, c(h) = 6.7335 angstrom for hexagonal unit cells. Density of material was found 5.52 gm/cm(3) (92.9% of theoretical one) in the sample sintered at 950 degrees C. The temperature dependent dielectric constant exhibits a broad peak at 538K (epsilon(m) = 2270) at 1 kHz that shows frequency dependent shifts toward higher temperature - typical relaxor behavior. Modified Curie-Weiss law was used to fit the dielectric data that exhibits almost complete diffuse phase transition characteristics. The dielectric relaxation obeys the Vogel-Fulcher relationship with the freezing temperature 412.4 K. Significant dielectric dispersion is observed in low frequency regime in both components of dielectric response and a small dielectric relaxation peak is observed. Cole-Cole plots indicate polydispersive nature of the dielectric relaxation; the relaxation distribution increases with increase in temperature. (C) 2011 Elsevier B.V. All rights reserved.