Temperature dependent electrical transport characteristics of BaTiO3 modified lithium borate glasses (original) (raw)

ELECTRICAL CONDUCTIVITY AND DIELECTRIC RELAXATION OF LITHIUM ALUMINO BORATE GLASSES

Ion conducting glasses 30 Li2O: (70-X) B2O3): X Al2O3 have been prepared over wide range composition (x = 0, 5, 10, 15 and 20 mole %). The mixed former effect on lithium ion transport due to addition of Al2O3 in series of Lithium borate glasses have been investigated. The electrical conductivity and dielectric relaxation of these glasses was analyzed using Aligent LCR analyzer in frequency range (1Hz – 1MHz) at different temperature (323k – 623k). The decrease in conductivity with the addition of Al2O3 attributed to structural modification and formation of B – O – Al Linkage resulting in reduces migration of Li+ ions along these bonds. The dielectric constants and modulus formalism is used to described the dielectric relaxation.

Structural properties and electrical transport characteristics of modified lithium borate glass ceramics

Journal of Alloys and Compounds, 2017

The studied glass ceramics were obtained by subjecting (70B 2 O 3-29Li 2 O-1Dy 2 O 3)-xBT (where BT corresponds to barium titanate) glasses to a suitable heat treatment. The XRD study performed on these samples confirmed the presence of crystalline phases formed in the glass ceramics. Spectroscopic studies like FTIR and Raman showed the presence of various structural units like BO 3 , BO 4 , TiO 4 , TiO 6 etc. Analysis of the FTIR spectra also depicts an increase in non bridging oxygens (NBO's) upon addition of BT. Electrical data of the samples has been analyzed in the framework of modulus and ac conductivity formalism. For this purpose the dielectric measurements as a function of temperature have been carried out on these samples in frequency range 1 Hz-10 6 Hz. Experimental data of imaginary part of the electric modulus has been fitted to nonexponential Kohlrausch-Williams-Watts (KWW) function whereas ac conductivity has been analyzed using Jonscher's universal power law. A close agreement in the values of activation energy determined from electric modulus (E r) and dc conductivity (E dc) indicated the involvement of similar type of charge barriers in both relaxation and conduction processes. The observed decrease in the activation energy could be

Electrical characterization of lithium bismuth borate glasses containing cobalt/vanadium ions

Solid State Ionics, 2017

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•V 2 O 5)•(30 − x)Li 2 O•20Bi 2 O 3 •50B 2 O 3 (x = 0.0, 2.0, 5.0, 7.0 and 10.0 mol%), 7CoO•23Li 2 O•20Bi 2 O 3 •50B 2 O 3 and 7V 2 O 5 •23Li 2 O•20Bi 2 O 3 •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°C-400°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′ (ω) vs. Z″ (ω)) 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.

Dielectric properties of Li2O3B2O3 glasses

Journal of Applied Physics, 2009

The frequency and temperature dependence of the dielectric constant and the electrical conductivity of the transparent glasses in the composition Li 2 O-3B 2 O 3 (LBO) were investigated in the 100 Hz-10 MHz frequency range. The dielectric constant and the loss in the low frequency regime were electrode material dependent. Dielectric and electrical relaxations were respectively analyzed using the Cole-Cole and electric modulus formalisms. The dielectric relaxation mechanism was discussed in the framework of electrode and charge carrier (hopping of the ions) related polarization using generalized

Electrical transport properties of 0.5Li2O–0.5M2O–2B2O3 (M=Li, Na and K) glasses

Journal of Non-Crystalline Solids, 2011

Transparent glasses in the system 0.5Li 2 O-0.5M 2 O-2B 2 O 3 (M=Li, Na and K) were fabricated via the conventional melt quenching technique. Amorphous and glassy nature of the samples were confirmed via the X-ray powder diffraction and the differential scanning calorimetry, respectively. The frequency and temperature dependent characteristics of the dielectric relaxation and the electrical conductivity were investigated in the 100 Hz-10 MHz frequency range. The imaginary part of the electric modulus spectra was modeled using an approximate solution of Kohrausch-Williams-Watts relation. The stretching exponent, β, was found to be temperature independent for 0.5Li 2 O-0.5Na 2 O-2B 2 O 3 (LNBO) glasses. The activation energy associated with DC conductivity was found to be higher (1.25eV) for 0.5Li 2 O-0.5K 2 O-2B 2 O 3 (LKBO) glasses than that of the other glass systems under study. This could be attributed to the mixed cationic effect.

Author's personal copy Conductivity and dielectric relaxation in niobium alkali borate glasses

The frequency and temperature dependent conductivity investigations for alkali niobium borate glasses of composition xNb 2 O 5 Á (30 À x)M 2 O Á 70B 2 O 3 (where M ¼ Li, Na; x ¼ 0, 4, 8 mol%) have been carried out using impedance spectroscopy (IS). The complex impedance data have been analyzed by using both the conductivity and the electric modulus formalisms. The conductivity decreases with the decrease in M 2 O:Nb 2 O 5 ratio. The effect of temperature on the scaling of dielectric modulus indicates that the conductivity relaxation mechanism is temperature independent. The overlapping of the normalized peaks corresponding to impedance and electric modulus and the identical values of thermal activation energy for conduction and relaxation suggest the single mechanism for the dynamic processes occurring in the present glasses. The variation of density, molar volume and glass transition temperature with glass composition has also been reported to supplement the conductivity results.

Electrical conductivity and relaxation frequency of lithium borosilicate glasses

Solid State Ionics, 2004

Electrical conductivity of glasses from the system 0.40Li 2 OÁ0.60(xB 2 O 3 (1 À x)Si 2 O 4) (0 V x V 1) were measured by impedance spectroscopy. The influence of the substitution of the first glass former by the second in electrical conductivity and in the parameters of the Arrhenius expression, i.e., activation energy and pre-exponential factor, is discussed. The electrical conductivity increases from the silica to the boron oxide region, with an anomaly at x = 0.3 but with no evidence of a mixed glass-former effect. The relaxation frequency, which is an intrinsic characteristic of each glass sample and is independent of geometrical parameters, was also deduced from impedance diagrams and are also presented for all compositions.

Conductivity and dielectric relaxation in niobium alkali borate glasses

Physica B-condensed Matter, 2010

Study of Electrical Conductivity of Lithium Borate Ionically Conducting Glasses

– Alkali ion conductors are of considerable interest because of their possible applications in solid state battery systems. The highly electropositive alkali ion provides the possibility of large cell voltage and very high energy densities. In general, particular material will be required to act as either an electrode or an electrolyte. Both application required high ionic conductivity, preferably at ambient or relatively low temperature. Lithium has a lower equivalent weight than sodium or potassium. It is also more electropositive and thus, provides the greater cell voltage than other two ions. Lithium has additional advantage that it can be handling more easily at room temperature than other alkali metals. On the basis of theoretical background and considering the advantage of amorphous solid electrolyte it was thought imperative to develop a lithium borate glass base solid electrolyte.

Dielectric Properties and Conductivity of Some Alkali Borate Glasses Doped With Cobalt Oxide

2012

Glass samples of a mixed alkali borate glasses doped with cobalt oxide have been prepared by the melt quenching technique in air atmosphere. The glassy state of the samples is characterized using X-ray diffraction. Glass-transition temperatures are measured using differential scanning calorimetery (DSC). A.C. Conductivity (σa.c), real and imaginary parts of the impedance of the prepared samples have been measured in the frequency range (42Hz-5MHz). The measurements were carried out in the temperature range (303-468K). The total conductivity as well as the frequency exponent, S, were determined from the dielectric spectrum, also the activation energy was calculated and discussed.

Temperature dependent electrical transport characteristics of BaTiO3 modified lithium borate glasses (original) (raw)

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