Conductivity and dielectric relaxation in niobium alkali borate glasses

Sanghi, Sujata; Sheoran, A.; Agarwal, Ashish; Khasa, Satish

doi:10.1016/j.physb.2010.09.032

Cited by 19 publications

(7 citation statements)

References 24 publications

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“…Relaxation peaks with different widths and locations were obtained for different SR samples. An ideal dielectric or polymer with a low mobile carrier concentration exhibits Debye relaxation, where the relaxation time function φ ( t ) is a simple exponential [23]. In this study, non‐Debye behaviours of M'' spectra were found in all SR samples, implying a distribution of relaxation times.…”

Section: Results and Analysismentioning

confidence: 57%

“…In this study, non‐Debye behaviours of M'' spectra were found in all SR samples, implying a distribution of relaxation times. The relaxation function φ ( t ) can be given by the Kohlrausch–Williams–Watts (KWW) function [23, 24]

\varphi (t)=\mathrm{exp}{\left(-\left(\frac{t}{{\tau }_{\mathrm{p}}}\right)\right. }^{\beta })

where τ p is the relaxation time, β is the stretched exponent in the range of 0 < β < 1, and represents the departure from the linear exponential ( β = 1).…”

Section: Results and Analysismentioning

confidence: 99%

“…In this study, non-Debye behaviours of M'' spectra were found in all SR samples, implying a distribution of relaxation times. The relaxation function φ (t) can be given by the Kohlrausch-Williams-Watts (KWW) function [23,24]…”

Section: Complex Modulus Analysis Of Srmentioning

confidence: 99%

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Analysis of conductance and interfacial polarisation behaviours of silicone rubber based on frequency domain spectroscopy

Jia

Wang

et al. 2023

High Voltage

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Silicone rubber (SR) is widely used for cable insulation and operates in multi‐stress coupling conditions. Its dielectric properties and ageing performance are the essential factors affecting cable operation. In this study, the frequency domain spectroscopy of unaged SR and SR aged under various conditions is measured. The dielectric responses before and after ageing are analysed in depth by the conjoint analysis via multiple complex planes (permittivity, conductivity, and modulus). Typical conductivity and interfacial polarisation properties, as well as property changes resulting from thermal and tensile ageing, are examined. Experimental results show that tensile ageing promotes conductance and interfacial polarisation ,while thermal ageing shows the opposite effects. Based on the multi‐core model and charge carrier hopping transport model, thermal and tensile ageing mechanisms on the conductance and interfacial polarisation behaviours of SR are demonstrated. Both behaviours exhibit positively correlated changing characteristics, suggesting that the two behaviours may originate from a common process. The carrier transport process, promoted by the tensile effect and slightly suppressed by the thermal effect, is the primary factor and considered an important indicator to evaluate the dielectric properties of SR insulation.

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Section: Results and Analysismentioning

confidence: 57%

\varphi (t)=\mathrm{exp}{\left(-\left(\frac{t}{{\tau }_{\mathrm{p}}}\right)\right. }^{\beta })

where τ p is the relaxation time, β is the stretched exponent in the range of 0 < β < 1, and represents the departure from the linear exponential ( β = 1).…”

Section: Results and Analysismentioning

confidence: 99%

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Analysis of conductance and interfacial polarisation behaviours of silicone rubber based on frequency domain spectroscopy

Jia

Wang

et al. 2023

High Voltage

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“…Activation energies for r = 0.111 to 0.428 are comparable with alkali borate glasses with low concentrations of TMO. 22 It can be seen from figure 4 inset that the conductivity shows a deep minimum at r = 0.538. This may be due to the crossover from one conduction mechanism to another.…”

Section: Resultsmentioning

confidence: 91%

Conductivity studies on microwave synthesized glasses

et al. 2015

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Conductivity measurements have been made on xV 2 O 5 − (100 − x) [0.5 Na 2 O + 0.5 B 2 O 3 ] (where 10 ≤ x ≤ 50) glasses prepared by using microwave method. DC conductivity (σ ) measurements exhibit temperatureand compositional-dependent trends. It has been found that conductivity in these glasses changes from the predominantly 'ionic' to predominantly 'electronic' depending upon the chemical composition. The dc conductivity passes through a deep minimum, which is attributed to network disruption. Also, this nonlinear variation in σ dc and activation energy can be interpreted using ion-polaron correlation effect. Electron paramagnetic resonance (EPR) and impedance spectroscopic techniques have been used to elucidate the nature of conduction mechanism. The EPR spectra reveals, in least modified (25 Na 2 O mol%) glasses, conduction is due to the transfer of electrons via aliovalent vanadium sites, while in highly modified (45 Na 2 O mol%) glasses Na + ion transport dominates the electrical conduction. For highly modified glasses, frequency-dependent conductivity has been analysed using electrical modulus formalism and the observations have been discussed.

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“…Niobium ions can also have difference oxidation states (Nb 4+ and Nb 5+ ), and although for most glasses the predominant state is Nb 5+ (related to the formation of NbO 6 structural units), in some phosphate glasses niobium ions can change their coordination state, which enables them to act as network former or modifier [43]. For that matter, not only the tungsten cations, but also the niobium ions can contribute to the electronic conductivity.…”

Section: Electrical Measurementsmentioning

confidence: 99%