화학공학소재연구정보센터
Solid State Ionics, Vol.312, 21-31, 2017
Electrical characterization of lithium bismuth borate glasses containing cobalt/vanadium ions
The present work reports the frequency, temperature and composition dependence of ac & dc conductivity, dielectric constant and impedance spectroscopic parameters for glass system having composition x (2CoO center dot V2O5)center dot(30 - x)Li2O center dot 20Bi(2)O(3)center dot 50B(2)O(3) (x = 0.0, 2.0, 5.0, 7.0 and 10.0 mol%), 7CoO center dot 23Li(2)O center dot 20Bi(2)O(3)center dot 50B(2) O-3 and 7V(2)O(5)center dot 23Li(2)O center dot 20Bi(2)O(3)center dot 50B(2)O(3) synthesized through melt-quench route. The investigations are carried out overwide ranges of frequency (1 kHz-5 MHz) and temperature (100 degrees C-400 degrees C). The effects of mixed-transition metal ions (i.e. Co and/or V-ions) on ac conductivity and dielectric properties have been investigated using impedance spectroscopy. Jonscher power law (JPL) is observed to be followed by all synthesized glass compositions. A synergic change in values of all electric and dielectric parameters at 7.0 mol% confirms the structural modification due to mixed transition metal ion effect in present glass system. Electric modulus of prepared glass samples exhibits an asymmetric peak for the imaginary part (M '') reflecting a non-Debye type relaxation. The complex impedance curves (Z' (omega) vs. Z '' (omega)) for all glass samples were plotted and found to exhibit good single well-shaped semi circles over the studied temperature range which depicts a single conduction mechanism. Dc conductivity at constant applied voltage (10 Volts) is also measured. Conductivity plots and electric modulus spectra were scaled according to the Summerfield Scaling Model. Both scaling behavior reflected the time temperature superposition principal and temperature independent conduction mechanism in the present glass system.