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    • Keywords


      PTCR; valence-compensated ceramic; impedance analysis

    • Abstract


      The electrical behaviour of valence-compensated ceramic system Ba1−xLaxTi1−xCoxO3 has been studied as a function of temperature (300–600 K) and composition (x ⩽ 0·20), using the method of impedance spectroscopy. The necessary equivalent circuit models that represent the data best have been obtained using impedance and modulus formalisms and grain and grain boundary contributions have been separated out. The compositionsx = 0·20 and 0·10 show a negative temperature coefficient of resistance (NTCR) behaviour whereas a very small variation of the grain and grain boundary resistance with temperature is observed forx = 0·05. A positive temperature coefficient of resistance (PTCR) behaviour having two ferroelectric components is observed forx = 0·01. These results reveal limitations in current theories of the PTCR effect.

    • Author Affiliations


      Lakshman Pandey1 Rajesh K Katare1 Om Parkash1 2 Devendra Kumar1 3

      1. Department of Physics, Rani Durgavati University, Jabalpur - 482 001, India
      2. School of Materials Science and Technology, Banaras Hindu University, Varanasi - 221 005, India
      3. Department of Ceramic Engineering, Institute of Technology, Banaras Hindu University, Varanasi - 221 005, India
    • Dates

  • Bulletin of Materials Science | News

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      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
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