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Dielectric relaxation studies in single and mixed alkali doped cobalt-borate glasses

N. NAGARAJA1, T. SANKARAPPA1,* , M. PRASHANT KUMAR1, SANTOSH KUMAR1, P. J. SADASHIVAIAH1

Affiliation

  1. Department of Physics, Gulbarga University, Gulbarga 585 106, Karnataka, India

Abstract

The cobalt-borate glasses containing Li and Li-K ions in single and mixed proportions have been investigated for dielectric properties in the frequency range 50Hz to 5MHz and temperature range 300K to 600K. The dielectric constant and loss were found to decrease with increase in frequency in both the series of glasses. Activation energies for dielectric loss derived by employing Hunt’s model indicated that the relaxation process has a local character and can be described by hops between pairs of sites. Activation energies for dielectric loss process were found to be in close agreement with dc activation energies. BNN’s linear relation between ac and dc conductivities has been verified in both the glass systems. It is for the first time that Hunts and BNN’s theories have been verified in cobalt-alkali doped borate glasses.

Keywords

Borate glasses, Transition metal ions, Alkali ions, Dielectric relaxation processes, Activation energies.

Citation

N. NAGARAJA, T. SANKARAPPA, M. PRASHANT KUMAR, SANTOSH KUMAR, P. J. SADASHIVAIAH, Dielectric relaxation studies in single and mixed alkali doped cobalt-borate glasses, Optoelectronics and Advanced Materials - Rapid Communications, 2, 1, January 2008, pp.22-25 (2008).

Submitted at: Dec. 12, 2007

Accepted at: Jan. 16, 2008