AC conductivity and its scaling behavior in lithium and sodium bismuthate glasses

Murugaraj, R.; Govindaraj, G.; George, Deepa

doi:10.1016/s0167-577x(02)01047-9

Cited by 71 publications

(25 citation statements)

References 24 publications

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“…As typically found in ionic conducting material [19], the frequency region of constant conductivity extends to higher frequencies with increasing temperature. In general, the phenomena of the conductivity-frequency dispersion is analyzed using the Jonscher's universal power law [20,21]:…”

Section: Resultsmentioning

confidence: 99%

Transport properties of hexanoyl chitosan-based gel electrolyte

Winie

Arof

2006

Ionics

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Films of hexanoyl chitosan-based polymer electrolyte were prepared by the technique of solution casting. The effect of plasticizer on the transport properties of hexanoyl chitosan:lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) electrolytes have been investigated. The plasticizer used was ethylene carbonate (EC). The highest room temperature conductivity achieved in the ECplasticized hexanoyl chitosan-based electrolytes is 2.75×10 −5 S cm −1 . The Rice and Roth model was used to explain the variations in the dc conductivity observed. The exponent, s, in Jonscher's universal power law equation σ(ω)=σ dc +Aω s , was analyzed as a function of temperature for the sample containing 30 wt% of EC. The analysis suggests that the conduction mechanism follows that proposed by the overlapping large polaron tunneling model.

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Section: Resultsmentioning

confidence: 99%

Transport properties of hexanoyl chitosan-based gel electrolyte

Winie

Arof

2006

Ionics

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“…In general, the phenomena of the ac conductivity dispersion is analyzed using the Jonscher's universal power law [9,22].…”

Section: Resultsmentioning

confidence: 99%

Dielectric behaviour and AC conductivity of LiCF3SO3 doped H-chitosan polymer films

Winie

Arof

2004

Ionics

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Abstract. H-chitosan that exhibited solubility in THF was prepared by acyl modification of chitosan. Films of H-chitosan containing LiCF3SO 3 were prepared by the solution cast technique. The effect of salt concentration on the frequency-dependent dielectric properties of H-chitosan: LiCF3SO 3 complexes were investigated by impedance spectroscopy, in the temperature range from 243 to 373 K. The dielectric properties and ac conductivity of the samples prepared have been analyzed. The dielectric constant increases sharply with temperature in the low frequency region. At higher frequencies, the effect of temperature on the dielectric constant is negligible. The values of dielectric constant were also found to increase with increasing conductivity of the samples. The imaginary part, Mi of electrical modulus shows the formation of dispersion peak. Relaxation times for the ionic charge carriers were extracted from the loss tangent maximum peak at various temperatures. The plot of relaxation times as a function of temperature shows Arrhenius type behaviour. The ac conductivity was found to obey the universal power law and as the temperature increases, the feature of ~3(co) ~ co n is more predominant. The temperature dependence of the power law exponent n is reasonably interpreted by the overlapping large polaron tunneling (OLPT) model.

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“…This behavior implies the onset of conductivity relaxation. The strong frequency dispersion of the ac conductivity is because the inhomogeneities in the glasses may be of a microscopic scale in nature with the distribution of relaxation processes through distribution of energy barriers [30]. The temperature and frequency dependences of the ac conductivity for other glass compositions are qualitatively similar.…”

Section: Ac Conductivitymentioning

confidence: 89%

Structure and electrical conductivity relaxation studies of Nb2O5-doped B2O3–Bi2O3–LiF glasses

Shaaban

2012

J Mater Sci

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Glasses with composition (70 -x) B 2 O 3 Á15Bi 2 O 3 Á15LiFÁxNb 2 O 5 with x = 0-1.0 mol% were prepared by conventional glass-melting technique. The molar volume V m values decrease and the glass transition temperatures T g increase with increase of Nb 2 O 5 content up to 0.2 mol%, which indicates that Nb 5? ions act as a glass former. Beyond 0.2 mol% Nb 2 O 5 the V m increases and the T g decreases, which suggests that Nb 5? ions act as a glass modifier. The FTIR spectra suggest that Nb 5? ions are incorporated into the glass network as NbO 6 octahedra, substituting BO 4 groups. The temperature dependence of the dc conductivity follows the Greaves variable range hopping model below 454 K, and follows the small polaron hopping model at temperatures [454 K. r dc , r ac conductivity and dielectric constant (e) decrease and activation energy for dc conduction DE dc which increases with increasing Nb 2 O 5 content up to 0.2 mol%, whereas r dc , r ac and (e) increase and DE dc decreases with increasing Nb 2 O 5 content beyond 0.2 mol%. The impedance spectroscopy shows a single semicircle or arcs which indicate only the ionic conduction mechanism. The electric modulus formalism indicates that the conductivity relaxation is occurring at different frequencies exhibit temperatureindependent dynamical process. The (FWHM) of the normalized modulus increases with increase in Nb 2 O 5 content suggesting that the distribution of relaxation times is associated with the charge carriers Li ? or F -ions in the glass network.

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AC conductivity and its scaling behavior in lithium and sodium bismuthate glasses

Cited by 71 publications

References 24 publications

Transport properties of hexanoyl chitosan-based gel electrolyte

Transport properties of hexanoyl chitosan-based gel electrolyte

Dielectric behaviour and AC conductivity of LiCF3SO3 doped H-chitosan polymer films

Structure and electrical conductivity relaxation studies of Nb2O5-doped B2O3–Bi2O3–LiF glasses

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