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
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spelling	my-uitm-ir.843462024-08-21T23:20:44Z 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 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 https://ir.uitm.edu.my/id/eprint/84346/ https://ir.uitm.edu.my/id/eprint/84346/1/84346.pdf text en public masters Universiti Teknologi MARA (UiTM) Faculty of Applied Physics Hisam@Hasham, Rosdiyana
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
advisor	Hisam@Hasham, Rosdiyana
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
qualification_level	Master's degree
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
granting_institution	Universiti Teknologi MARA (UiTM)
granting_department	Faculty of Applied Physics
publishDate	2019
url	https://ir.uitm.edu.my/id/eprint/84346/1/84346.pdf
_version_	1811768700931407872

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

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