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    • Keywords


      Ceramic; sol–gel processes; magnetic measurements; electronic transport; X-ray diffraction.

    • Abstract


      In this paper we report the investigation of transition metal oxide compound, La0.67Ca0.25Sr0.04Ba0.04MnO3 (LCSBMO), along with La0.67Ca0.33MnO3 (LCMO), synthesized by sol–gel route under identical conditions. The effect of simultaneous low level substitution of large size ions such as Sr2+ and Ba2+ for Ca2+ ions on the electronic transport and magnetic susceptibility properties are analysed and compared apart from microstructure and lattice parameters. The temperature dependent electrical transport of the polycrystalline pellets of LCSBMO and LCMO when obeying the well studied law, ρ = ρ0 + ρ2 𝑇2 for 𝑇 < 𝑇MI, is observed to differ by more than 50% from the values of ρ0 and ρ2, with the former compound showing enhanced electrical conductivity than the latter. Similarly in fitting the adiabatic small polaron model for resistivity data of both the samples for 𝑇 > 𝑇MI, the polaron activation energy is found to differ by about 11%. In addition, the temperature dependent a.c. magnetic susceptibility study of the compounds shows a shift of about 6% in the paramagnetic to ferromagnetic transition temperature (285 K for LCSBMO and 270 K for LCMO).

    • Author Affiliations


      B Munirathinam1 M Krishnaiah1 M Manivel Raja2 S Arumugam3 K Porsezian4

      1. Department of Physics, Sri Venkateswara University, Tirupati 517 502, India
      2. Advanced Magnetics Group, Defence Metallurgical Research Laboratory, Hyderabad 500 058, India
      3. Department of Physics, Bharathidasan University, Tiruchirapalli 620 024, India
      4. Department of Physics, Pondicherry University, Puducherry 605 014, India
    • Dates

  • Bulletin of Materials Science | News

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