Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ 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...
| Prif Awdur: | |
|---|---|
| Fformat: | Traethawd Ymchwil |
| Iaith: | English |
| Cyhoeddwyd: |
2011
|
| Pynciau: | |
| Mynediad Ar-lein: | https://ir.uitm.edu.my/id/eprint/17656/13/17656.pdf |
| _version_ | 1825734891087593472 |
|---|---|
| author | Ali Yusuf, Azliza |
| author_facet | Ali Yusuf, Azliza |
| author_sort | Ali Yusuf, Azliza |
| collection | UITM |
| 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. |
| first_indexed | 2024-03-06T01:38:45Z |
| format | Thesis |
| id | oai:ir.uitm.edu.my:17656 |
| institution | Universiti Teknologi MARA |
| language | English |
| last_indexed | 2024-03-06T01:38:45Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oai:ir.uitm.edu.my:176562022-11-24T04:15:07Z https://ir.uitm.edu.my/id/eprint/17656/ Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf Ali Yusuf, Azliza Q Science (General) QD Chemistry 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. 2011-09 Thesis NonPeerReviewed text en https://ir.uitm.edu.my/id/eprint/17656/13/17656.pdf Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf. (2011) Masters thesis, thesis, Universiti Teknologi MARA (UiTM). <http://terminalib.uitm.edu.my/17656.pdf> |
| spellingShingle | Q Science (General) QD Chemistry Ali Yusuf, Azliza Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf |
| title | Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf |
| title_full | Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf |
| title_fullStr | Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf |
| title_full_unstemmed | Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf |
| title_short | Effects of Germanium substitutions at Cu/Sr sites on fluctuation induced conductivity and interplanar coupling of TI₀.₈₅Cr₀.₁₅Sr₂CaCu₂O₇₋₈ superconductor / Azliza Ali Yusuf |
| title_sort | effects of germanium substitutions at cu sr sites on fluctuation induced conductivity and interplanar coupling of ti₀ ₈₅cr₀ ₁₅sr₂cacu₂o₇₋₈ superconductor azliza ali yusuf |
| topic | Q Science (General) QD Chemistry |
| url | https://ir.uitm.edu.my/id/eprint/17656/13/17656.pdf |
| work_keys_str_mv | AT aliyusufazliza effectsofgermaniumsubstitutionsatcusrsitesonfluctuationinducedconductivityandinterplanarcouplingofti085cr015sr2cacu2o78superconductorazlizaaliyusuf |