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Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi

Mixed glass former of composition 70[xTeO2+(l-x)B2O3J+15Na2O+15K2O where x = 0 - 0.7 mol% have been prepared by melt quenching method to investigate their structural, AC conductivity, dielectric and optical properties. The variation of conductivity (er') with Te02 showed a non-linear behaviour,...

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Main Author: Shuhaimi, Shima Asyurah
Format: Thesis
Language:English
Published: 2019
Subjects:
Dielectrics
Online Access:https://ir.uitm.edu.my/id/eprint/84346/1/84346.pdf
https://ir.uitm.edu.my/id/eprint/84346/
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spelling my.uitm.ir.843462024-08-21T23:20:44Z https://ir.uitm.edu.my/id/eprint/84346/ Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi Shuhaimi, Shima Asyurah Dielectrics Mixed glass former of composition 70[xTeO2+(l-x)B2O3J+15Na2O+15K2O where x = 0 - 0.7 mol% have been prepared by melt quenching method to investigate their structural, AC conductivity, dielectric and optical properties. The variation of conductivity (er') with Te02 showed a non-linear behaviour, where decrease to a minimum value at x = 0.4 mol% before increasing for x > 0.4 mol%. The minimum is suggested to be due to low migration of Na+ and K+ ions caused by the mixed glass former effect (MGFE). Meanwhile, dielectric constant (e') showed a slight increase for x < 0.4 mol% followed by a large increase for x > 0.5 mol% Te02. This result is attributed to the formation of TeCb give out a larger effect compared to BO3 and is suggested to be related to MGFE. Structural analysis of the present glass system reveals N4 reached minima at x = 0.2 mol% and 0.4 mol% with addition of Te02 which attributed to the structural changes due to the conversion of BO4 to BO3 units. Glass transition temperature, Tg exhibited a non-linear increase for x < 0.5 mol% followed by a large increase at x > 0.5 mol%. The conduction mechanism at low frequency region was found to be Inverse - Overlapping Large Polaron Tunnelling (Inverse - OLPT) for x < 0.5 mol%, while the mechanism transformed to the OLPT model for x = 0.7 mol%. The electric modulus of the present glass system showed asymmetric peak of M\ that reflected a non-Debye type relaxation. The optical energy gap, E0pt for both transition exhibited a minimum at x = 0.4 mol%, whereas refractive index, n and Urbach energy, Eu showed a maxima at the same concentration, thereby indicating variation in polarizability due to changes in concentration of bridging and nonbridging oxygen. On the other hand, the large decrease in ao2.and A for x > 0.2 mol% because of increasing number of bridging oxygen attributed to BO4 that increase the covalency and decrease the electron donor power. The changes observed showed that the continuous addition of Te02 into the glass system influence the properties of this borotellurite glasses. 2019 Thesis NonPeerReviewed text en https://ir.uitm.edu.my/id/eprint/84346/1/84346.pdf Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi. (2019) Masters thesis, thesis, Universiti Teknologi MARA (UiTM). <http://terminalib.uitm.edu.my/84346.pdf>
institution Universiti Teknologi Mara
building Tun Abdul Razak Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Mara
content_source UiTM Institutional Repository
url_provider http://ir.uitm.edu.my/
language English
topic Dielectrics
spellingShingle Dielectrics
Shuhaimi, Shima Asyurah
Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi
description Mixed glass former of composition 70[xTeO2+(l-x)B2O3J+15Na2O+15K2O where x = 0 - 0.7 mol% have been prepared by melt quenching method to investigate their structural, AC conductivity, dielectric and optical properties. The variation of conductivity (er') with Te02 showed a non-linear behaviour, where decrease to a minimum value at x = 0.4 mol% before increasing for x > 0.4 mol%. The minimum is suggested to be due to low migration of Na+ and K+ ions caused by the mixed glass former effect (MGFE). Meanwhile, dielectric constant (e') showed a slight increase for x < 0.4 mol% followed by a large increase for x > 0.5 mol% Te02. This result is attributed to the formation of TeCb give out a larger effect compared to BO3 and is suggested to be related to MGFE. Structural analysis of the present glass system reveals N4 reached minima at x = 0.2 mol% and 0.4 mol% with addition of Te02 which attributed to the structural changes due to the conversion of BO4 to BO3 units. Glass transition temperature, Tg exhibited a non-linear increase for x < 0.5 mol% followed by a large increase at x > 0.5 mol%. The conduction mechanism at low frequency region was found to be Inverse - Overlapping Large Polaron Tunnelling (Inverse - OLPT) for x < 0.5 mol%, while the mechanism transformed to the OLPT model for x = 0.7 mol%. The electric modulus of the present glass system showed asymmetric peak of M\ that reflected a non-Debye type relaxation. The optical energy gap, E0pt for both transition exhibited a minimum at x = 0.4 mol%, whereas refractive index, n and Urbach energy, Eu showed a maxima at the same concentration, thereby indicating variation in polarizability due to changes in concentration of bridging and nonbridging oxygen. On the other hand, the large decrease in ao2.and A for x > 0.2 mol% because of increasing number of bridging oxygen attributed to BO4 that increase the covalency and decrease the electron donor power. The changes observed showed that the continuous addition of Te02 into the glass system influence the properties of this borotellurite glasses.
format Thesis
author Shuhaimi, Shima Asyurah
author_facet Shuhaimi, Shima Asyurah
author_sort Shuhaimi, Shima Asyurah
title Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi
title_short Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi
title_full Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi
title_fullStr Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi
title_full_unstemmed Effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xTeO2+(1-x)B2O3]+15Na2O+15K2O glasses / Shima Asyurah Shuhaimi
title_sort effects of mixed glass former on ac conductivity, dieletric and optical properties of 70[xteo2+(1-x)b2o3]+15na2o+15k2o glasses / shima asyurah shuhaimi
publishDate 2019
url https://ir.uitm.edu.my/id/eprint/84346/1/84346.pdf
https://ir.uitm.edu.my/id/eprint/84346/
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score 13.211869

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