Structure, Ionic Conductivity and Mixed Alkali Effect in Li\(_2\)O and Na\(_2\)O Doped Borate Glasses
Prashantkumar M
Department of Physics, Government First Grade College Shahapur, Karnataka, 585 223, India.
Arunkumar V Banagar *
Department of Physics, Government College (Autonomous), Kalaburagi, Karnataka, 585 105, India.
N. Nagaraja
Department of Physics, VTURC, Rao Bahadur Y. Mahabaleswarappa Engineering College, Ballari, Karnataka, 583104, India.
*Author to whom correspondence should be addressed.
Abstract
In this paper, we report the bulk density, structure and temperature dependent ionic conductivity in B2O3(1-x) – (Li2O1/2 + Na2O1/2) x mixed-alkali glass systems. The non-crystalline nature of the melt-quenched glass samples has been established by XRD studies. The compositional dependence of density was found to be non-linear. FT-IR studies revealed the formation of BO3 to BO4groups with the addition of alkali content. The DC conductivity of the present samples in the temperature range from 313K to 473K was measured by two-probe method. The ionic conductivity decreased with increase in alkali content up to x=0.30 and it increased for further doping of alkali content. The activation energy at high temperature region is found to increase initially and attained maxima at x = 0.3 and decreased for further doping. The ionic conductivity and activation energy have respectively attained a minima and maxima at x = 0.30 of alkali. This kind of behavior has been ascribed to the occurrence of mixed alkali effect in the present glass systems.
Keywords: Borate Glasses, mixed alkali effect, ft-ir, ionic conductivity, activation energy, XRD