Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf

This thesis describes the effects of Germanium (Ge) substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of T11212 layered structure. Two series of T11212 superconductors were synthesized from TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ (х=0-0.6) and TI₀.₈₅ Cr₀.₁₅ Sr₂ CaCu₂₋ₓGeₓO₇...

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Main Author:	Ali Yusuf, Azliza
Format:	Thesis
Language:	English
Published:	2011
Online Access:	http://ir.uitm.edu.my/id/eprint/17656/ http://ir.uitm.edu.my/id/eprint/17656/8/TM_AZLIZA%20ALI%20YUSUF%20AS%2011_5.pdf

id	uitm-17656
recordtype	eprints
spelling	uitm-176562018-11-21T06:05:54Z http://ir.uitm.edu.my/id/eprint/17656/ Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf Ali Yusuf, Azliza This thesis describes the effects of Germanium (Ge) substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of T11212 layered structure. Two series of T11212 superconductors were synthesized from TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ (х=0-0.6) and TI₀.₈₅ Cr₀.₁₅ Sr₂ CaCu₂₋ₓGeₓO₇₋₈ (y=0-0.3) nominal starting compositions using the conventional solid state method. Substitution of Ge⁴⁺ in place of Cu in TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ (х=0-0.6) series showed initial increase in zero critical temperature value, Tc zero from 98 K (x=0) to 100 K (x=0.1) and in the range of 85-86 K for x= 0.2-0.3. The slow decrease in Tc zero is unexpected as tetravalent Ge⁴⁺ substitution is expected to strongly reduce hole concentration in the samples and suppress Tc zero.While for substitution of Ge⁴⁺ in place of Sr in TI₀.₈₅ Cr₀.₁₅ Sr₂ CaCu₂₋ₓGeₓO₇₋₈ (y=0-0.3) series, electrical resistance measurements showed the zero critical temperature value, Tc zero were in the range of 90-98 K for.y=0 - 0.15 and in range of 60-78 K forj;= 0.2-0.3. Analysis of excess conductivity behavior based on Aslamazov-Larkin model for the Ge free compound, revealed a 2D fluctuation behavior. However, substitution of Ge in both of the series induced 2D to 3D transition behavior with the highest transition temperature, T2D-3D observed at x= 0.10 and y= 0.10 samples. The analyses of Fourier transformation infrared (FTIR) and X-ray diffraction (XRD) data indicate increasing CuO inter-plane coupling with Ge substitution at both Cu and Sr-sites. The increment was suggested to cause sustenance of the high Tc zero and metallic normal state behavior for x= 0-0.30 and y= 0.03-0.15 samples. This is supported by the excess conductivity analysis using the Lawrence Doniach model which also indicates an increase in the inter-plane coupling (J) values. It was suggested that the increase in inter-plane coupling may enhance correlation between the carrier of the superconducting samples which then decrease the anisotropy and resulted to better superconducting properties of the samples. 2011 Thesis NonPeerReviewed text en http://ir.uitm.edu.my/id/eprint/17656/8/TM_AZLIZA%20ALI%20YUSUF%20AS%2011_5.pdf Ali Yusuf, Azliza (2011) Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf. Masters thesis, Universiti Teknologi MARA.
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Teknologi MARA
building	UiTM Institutional Repository
collection	Online Access
language	English
description	This thesis describes the effects of Germanium (Ge) substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of T11212 layered structure. Two series of T11212 superconductors were synthesized from TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ (х=0-0.6) and TI₀.₈₅ Cr₀.₁₅ Sr₂ CaCu₂₋ₓGeₓO₇₋₈ (y=0-0.3) nominal starting compositions using the conventional solid state method. Substitution of Ge⁴⁺ in place of Cu in TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ (х=0-0.6) series showed initial increase in zero critical temperature value, Tc zero from 98 K (x=0) to 100 K (x=0.1) and in the range of 85-86 K for x= 0.2-0.3. The slow decrease in Tc zero is unexpected as tetravalent Ge⁴⁺ substitution is expected to strongly reduce hole concentration in the samples and suppress Tc zero.While for substitution of Ge⁴⁺ in place of Sr in TI₀.₈₅ Cr₀.₁₅ Sr₂ CaCu₂₋ₓGeₓO₇₋₈ (y=0-0.3) series, electrical resistance measurements showed the zero critical temperature value, Tc zero were in the range of 90-98 K for.y=0 - 0.15 and in range of 60-78 K forj;= 0.2-0.3. Analysis of excess conductivity behavior based on Aslamazov-Larkin model for the Ge free compound, revealed a 2D fluctuation behavior. However, substitution of Ge in both of the series induced 2D to 3D transition behavior with the highest transition temperature, T2D-3D observed at x= 0.10 and y= 0.10 samples. The analyses of Fourier transformation infrared (FTIR) and X-ray diffraction (XRD) data indicate increasing CuO inter-plane coupling with Ge substitution at both Cu and Sr-sites. The increment was suggested to cause sustenance of the high Tc zero and metallic normal state behavior for x= 0-0.30 and y= 0.03-0.15 samples. This is supported by the excess conductivity analysis using the Lawrence Doniach model which also indicates an increase in the inter-plane coupling (J) values. It was suggested that the increase in inter-plane coupling may enhance correlation between the carrier of the superconducting samples which then decrease the anisotropy and resulted to better superconducting properties of the samples.
format	Thesis
author	Ali Yusuf, Azliza
spellingShingle	Ali Yusuf, Azliza Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf
author_facet	Ali Yusuf, Azliza
author_sort	Ali Yusuf, Azliza
title	Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf
title_short	Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf
title_full	Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf
title_fullStr	Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf
title_full_unstemmed	Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf
title_sort	effects of germanium substitutions at cu/sr sites on fluctuation induced conductivity and interplanar coupling of ti₀.₈₅ cr₂ cacu₂₋ₓgeₓo₇₋₈ superconductor / azliza ali yusuf
publishDate	2011
url	http://ir.uitm.edu.my/id/eprint/17656/ http://ir.uitm.edu.my/id/eprint/17656/8/TM_AZLIZA%20ALI%20YUSUF%20AS%2011_5.pdf
first_indexed	2023-09-18T22:58:46Z
last_indexed	2023-09-18T22:58:46Z
_version_	1777418032040116224

Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅ Cr₂ CaCu₂₋ₓGeₓO₇₋₈ superconductor / Azliza Ali Yusuf

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