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      https://www.ias.ac.in/article/fulltext/boms/038/04/0985-0993

    • Keywords

       

      Conductivity; electrical modulus; impedance; microwave; power law; stretched exponent.

    • Abstract

       

      Conductivity measurements have been made on 𝑥𝑉2O5 − (100 − 𝑥) [0.5 Na2O + 0.5 B2O3] (where 10 ≤ 𝑥 ≤ 50) glasses prepared by using microwave method. DC conductivity (𝜎) measurements exhibit temperature-and compositional-dependent trends. It has been found that conductivity in these glasses changes from the predominantly ‘ionic’ to predominantly ‘electronic’ depending upon the chemical composition. The dc conductivity passes through a deep minimum, which is attributed to network disruption. Also, this nonlinear variation in 𝜎dc and activation energy can be interpreted using ion–polaron correlation effect. Electron paramagnetic resonance (EPR) and impedance spectroscopic techniques have been used to elucidate the nature of conduction mechanism. The EPR spectra reveals, in least modified (25 Na2O mol%) glasses, conduction is due to the transfer of electrons via aliovalent vanadium sites, while in highly modified (45 Na2O mol%) glasses Na+ ion transport dominates the electrical conduction. For highly modified glasses, frequency-dependent conductivity has been analysed using electrical modulus formalism and the observations have been discussed.

    • Author Affiliations

       

      Asha Rajiv1 M Sudhakara Reddy1 R Viswanatha2 Jayagopal Uchil1 C Narayana Reddy3

      1. Department of Physics, School of Graduate Studies, Jain University, Bangalore 560027, India
      2. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
      3. Department of Physics, Sree Siddaganga College of Arts, Science and Commerce, Tumkur University, Tumkur 572103, India
    • Dates

       
  • Bulletin of Materials Science | News

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