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

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.