Electrical conduction in glass fibres subjected to a sodium to or from silver ion-exchange treatment

Chakravorty, D.; Shrivastava, Aroh

doi:10.1088/0022-3727/19/11/015

Cited by 19 publications

(17 citation statements)

References 11 publications

(3 reference statements)

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“…where p. is the pre-exponential factor, ~1 the activation energy, k the Boltzmann constant and T temperature. As observed in earlier studies on sodium/silver exchange in silicate glasses Shrivastava 1986, Chakravorty andMathews 1989) a critical electrical field is necessary for inducing the highconductivity state in the present glass system also. Figure 3 is a typical voltage+xrrent characteristic for ion-exchanged glass no 2 at a temperature of 182 "C. In this figure…”

Section: Resultssupporting

confidence: 77%

“…The electric-field-induced switching to a highly conducting state in all the ion-exchanged glasses in the present investigation is thought to arise due to the growth of silver-rich phase and formation of percolation paths (Chakravorty and Shrivastava 1986). The decrease of the critical electric field at which switching occurs as temperature increases confirms that this model is valid in the present glass system as well.…”

Section: Discussionsupporting

confidence: 79%

“…In all such glasses the silver or lithium content is very high, being typically of the order of 70 mol%. Some recent investigations have shown that a sodium/silver exchange of an oxide glass can induce very high electrical conductivity to the system (Chakravorty and Shrivastava 1986, Shrivastava and Chakravorty 1987, Chakravorty and Mathews 1989. The alkali content of these glasses ranges from 10 to 30 mol%.…”

Section: Introductionmentioning

confidence: 99%

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Fast ion conduction in lithia-containing glasses after ion exchange

Chakravorty

Kumar

Roy

1990

J. Phys. D: Appl. Phys.

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High electrical conductivity has been induced in silicate glasses containing Li20 after subjecting them to a lithiumisilver ion exchange treatment followed by a suitable combination of temperature and electric field. The roomtemperature resistivities of these switched samples range from 50 Q cm to 1000 Bcm. The activation energy for conduction has values in the range 0.01 to 0.16 eV. The critical electric field for switching is found to be of the order of a few volts per centimetre. The field-induced switching is explained on the basis of growth of a silver-rich phase to the percolation configuration. Wagner's asymmetric polarisation cell measurements show that the charge carriers are ionic in the glasses in their highly conducting states.

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Section: Resultssupporting

confidence: 77%

Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Fast ion conduction in lithia-containing glasses after ion exchange

Chakravorty

Kumar

Roy

1990

J. Phys. D: Appl. Phys.

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“…Measurements were carried out with a Hewlett-Packard 4192A impedance analyzer in the frequency range from 100 Hz to 1 MHz for temperatures varying from 448 to 577 K. The bulk electrical resistivity was determined from the complex impedance analysis of the frequency-dependent capacitance and conductance data. 23 The X-ray photoelectron spectra were obtained by the Scienta ESCA-300 spectrometer. An Al K␣ radiation with photon energy of 1486.67 eV was used as the X-ray source.…”

Section: Methodsmentioning

confidence: 99%

Dielectric Relaxation in Frequency Domain and X-ray Photoelectron Spectroscopy Studies on Na[sub 2]O-Al[sub 2]O[sub 3]-B[sub 2]O[sub 3] Glasses

Maity

2005

J. Electrochem. Soc.

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Dielectric modulus spectra of the glasses in the system Na 2 O-Al 2 O 3 -B 2 O 3 have been obtained from the impedance measurement and analyzed by a heterogeneous conductor ͑nanoscale level͒ model developed in the past years. Satisfactory agreement between the theory and the experiment has been observed. The ␤ exponent of the Kohlrausch-Williams-Watts ͑KWW͒ stretched exponential function appears to be correlated with the amount of the alkali ion fluctuation in the conducting phase of the glasses. The Na 1s X-ray photoelectron spectra provide evidence of the presence of the alkali ion fluctuation in these glasses.It has been established that the non-Debye processes ͑distribution of relaxation times͒ dominate in the real system. It has become customary to fit the ac impedance data of amorphous materials to a relaxation function incorporating the Kohlrausch-Williams-Watts ͑KWW͒ stretched exponential 1-3where R is the effective relaxation time and the exponent ␤ has a value in the range between 0 and 1. It gives a measure of the distribution of relaxation times within the system. The physical mechanism responsible for such a fractional value of ␤ has been a source of some controversy. The origin of the relaxation in ionically conducting glasses has been modeled 4 using diffusion-controlled relaxation process without assuming a distribution of relaxation times. The model can be regarded as a combined series and parallel relaxation process: in the series aspect the interionic interaction is associated with the diffusion triggering of relaxation at an interstitial site, and in the parallel aspect all such diffusion-controlled relaxation events occur independently. Non-Debye relaxation in amorphous conductors 5 was also explained by introducing the mutual interactions among mobile ion species of considerable concentration. The correlation between the decoupling index, which is the ratio of mechanical to dielectric relaxation times, and KWW stretching parameter was discussed by Hunt. 6 A general coupling theory 7,8 which is based on the cooperative effects between the species primarily responsible for the conductivity relaxation and the other surrounding equivalent ions has been proposed. Many of the predictions arising out of this model have been tested on several oxide glasses. 9,10 The model has also been found to be similar to a jump relaxation model. 11 The structure of the glasses and the distribution of the mobile ions within these glasses were either considered homogeneous or essentially disregarded in these models. At the end of the twentieth century, a different approach was developed to understand the non-Debye relaxation behavior of the oxide glasses. Based on a diagonal layer model 12 a spatial variation of the alkali ion concentration has been assumed in calculating the dielectric modulus spectra of several alkali silicate glasses. 13,14 Obviously this model will be applicable only to those glasses which do not possess a homogeneous distribution of the mobile ions. Satisfactory agreement between the experime...

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“…Measurements were carried out over the temperature range 230 to 330K with the temperature control being accurate to within + 1K. The bulk electrical resistivity was determined by the complex impedance analysis of the frequency-dependent capacitance and resistance data (Chakravorty and Shrivastava 1986).…”

Section: Methodsmentioning

confidence: 99%

Relaxation studies on V2O5-TeO2 glasses using heterogeneous conductor model

1994

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The dielectric modulus spectra of glasses in the system V2Os-TeO2 have been studied as a function Of frequency in the temperature range 230 to 330 K. A heterogeneous conductor model developed recently with the assumption of a sinusoidally varying local conductivity in the conducting phase has been successfully applied to analyse the data in this glass system. The Kohlrausch-Williams-Watts (KWW) stretched exponential function has also been used to fit the measured modulus spectra. The exponent fl is found to be correlated to the conductivity fluctuation in the conducting phase as assumed in the heterogeneous model.

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Electrical conduction in glass fibres subjected to a sodium to or from silver ion-exchange treatment

Cited by 19 publications

References 11 publications

Fast ion conduction in lithia-containing glasses after ion exchange

Fast ion conduction in lithia-containing glasses after ion exchange

Dielectric Relaxation in Frequency Domain and X-ray Photoelectron Spectroscopy Studies on Na[sub 2]O-Al[sub 2]O[sub 3]-B[sub 2]O[sub 3] Glasses

Relaxation studies on V2O5-TeO2 glasses using heterogeneous conductor model

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