• H S Tewari

      Articles written in Bulletin of Materials Science

    • Dielectric properties of the system Ca1 −xLaxTi1 −xCoxO3

      Ch Durga Prasad H S Tewari Devendra Kumar Om Parkash

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      Dielectric behaviour of samples of the system Ca1 −xLaxTi1 −xCoxO3 withx ⩽ 0·20 has been studied in the temperature range 300–525 K as a function of frequency. The strong dispersion ofɛ andD observed in these materials indicate the significant contribution of interfacial polarisation to the observed dielectric properties. The interfacial polarisation arises due to the presence of microscopic chemical heterogeneities arising out of the slow diffusion-controlled solid state sintering process used for their preparation.

    • Electrical conduction in the system Sr0·90La0·10Ti0·90M′0·10O3 (M′ = Co, Ni or Cr)

      H S Tewari R K Singh

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      We have successfully synthesized the system Sr1 −xLaxTi1 −xM′xO3 where M′ = Cr, Ni and Co by using conventional solid state ceramic method. Powder X-ray diffraction patterns of the different compositions show the formation of single phase materials. Measurement of AC conductivity as a function of frequency at different temperatures in the range 300–550 K show that conduction in these compositions occurs due to hopping of charge carriers between localized transition metal ion sites.

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