Structural and electrical properties of perovskite Ba(Sm1/2Nb1/2)O3-BaTiO3ceramic

Abstract

The structural and electrical properties of <TEX>$(1-x)Ba(Sm_{1/2}Nb_{1/2})O_3-xBaTiO_3$</TEX>; (<TEX>$0{\leq}x{\leq}1$</TEX>) ceramics were prepared by conventional ceramic technique at <TEX>$1375^{\circ}C$</TEX>/7 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were derived from the X-ray diffraction (XRD) data using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm m. Dielectric study revealed that the compound <TEX>$0.75Ba(Sm_{1/2}Nb_{1/2})O_3-0.25BaTiO_3$</TEX> is having low and <TEX>${\varepsilon}^{\prime}$</TEX> and <TEX>${\varepsilon}^{{\prime}{\prime}}$</TEX> a low <TEX>$T_{CC}$</TEX> (< 5%) in the working temperature range (up to+<TEX>$100^{\circ}C$</TEX>) which makes this composition suitable for capacitor application and may be designated as 'Stable Low-K' Class I material as per the specifications of the Electronic Industries Association. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in the system. The ac conductivity data were used to evaluate the density of states at Fermi level, minimum hopping length and apparent activation energy of the compounds.