Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh
In this work, the effect of tantalum (Ta) substitutions at the Sr-site on superconductivity of Tl0.9Bi0.1Sr2-xTaxCa0.9Y0.1Cu2O7 (x = 0 - 0.40) series and the effect of nanosize MgO particles on 1212 phase formation and transport critical current density, Jc in external magnetic field for Tl0.9Bi0.1S...
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| Format: | Thesis |
| Language: | English |
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2008
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| Online Access: | https://ir.uitm.edu.my/id/eprint/27693/1/TM_ZULZAMRI%20SALLEH%20AS%2008_5.pdf |
| _version_ | 1796902553515982848 |
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| author | Salleh, Zulzamri |
| author_facet | Salleh, Zulzamri |
| author_sort | Salleh, Zulzamri |
| collection | UITM |
| description | In this work, the effect of tantalum (Ta) substitutions at the Sr-site on superconductivity of Tl0.9Bi0.1Sr2-xTaxCa0.9Y0.1Cu2O7 (x = 0 - 0.40) series and the effect of nanosize MgO particles on 1212 phase formation and transport critical current density, Jc in external magnetic field for Tl0.9Bi0.1Sr1.95Ta0.05Ca0.9Y0.1Cu2O7 + yMgO (y = 0 - 0.8 wt.%) series and Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 + zMgO (z = 0 - 0.80 wt.%) series superconductors were investigated. Results of tantalum substitution at Sr-site in Tl0.9Bi0.1Sr2-xTaxCa0.9Y0.1Cu2O7 (x = 0 - 0.40) series showed that the best superconducting behavior occurred at x = 0.05 with Tconset of 96 K and Tczero of 65 K. Higher Ta substitution caused gradual deterioration of superconductivity, accompanied by a change of normal state behavior from metallic to semiconductor-like behavior with increasing Ta. SEM investigation showed changes in grain size with Ta substitution. Results of electrical measurements on Tl0.9Bi0.1Sr1.95Ta0.05Ca0.9Y0.1Cu2O7 + yMgO (y = 0 - 0.8 wt.%) series superconductor revealed the highest transport critical current density Jc (at 20 K) of28 A/cm2 at y = 0.2 wt.%. Samples withy = 0 - 0.40 wt.% showed a rapid drop of Jc at low fields (< 0.1 Tesla) before a slower deterioration at higher fields (> 0.1 Tesla). This indicates the presence of weak links at low fields and dominance of strong links at higher fields. The smallest drop of Jc was observed for sample y = 0.2 wt.%. SEM results for these series showed no significant difference in microstructure between MgO added samples. Results of electrical measurements on Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 + zMgO (z = 0 - 0.80 wt.%) series revealed the highest Jc (at 30 K) of 16 A/cm2 for z = 0.1 wt.%. The behavior of Jc in external fields also indicates presence of weak links at low fields. The smallest drop of Jc was observed for z = 0.1 wt.%. SEM micrographs of MgO added samples showed smaller grain size compared to pure samples. The enhanced Jc at y = 0.2 wt.% for the Tl0.9Bi0.1Sr1.9Ta0.05Ca0.9Y0.1Cu2O7 +yMgO series and z = 0.1 wt.% for the Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 + zMgO series is suggested to be due to flux pinning as a result of the MgO additions. In conclusion, substitution of Ta0.05 at Sr-site successfully stabilized the 1212-phase during synthesis of T11212 superconductors. The addition of a moderate amount of nano-MgO particle before final sintering improved transport critical current density and enhanced flux pinning ability of the Tl-1212 superconductors. |
| first_indexed | 2024-03-06T02:06:41Z |
| format | Thesis |
| id | uitm.eprints-7693 |
| institution | Universiti Teknologi MARA |
| language | English |
| last_indexed | 2024-03-06T02:06:41Z |
| publishDate | 2008 |
| record_format | dspace |
| spelling | uitm.eprints-76932020-02-05T07:21:32Z https://ir.uitm.edu.my/id/eprint/27693/ Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh Salleh, Zulzamri Electricity In this work, the effect of tantalum (Ta) substitutions at the Sr-site on superconductivity of Tl0.9Bi0.1Sr2-xTaxCa0.9Y0.1Cu2O7 (x = 0 - 0.40) series and the effect of nanosize MgO particles on 1212 phase formation and transport critical current density, Jc in external magnetic field for Tl0.9Bi0.1Sr1.95Ta0.05Ca0.9Y0.1Cu2O7 + yMgO (y = 0 - 0.8 wt.%) series and Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 + zMgO (z = 0 - 0.80 wt.%) series superconductors were investigated. Results of tantalum substitution at Sr-site in Tl0.9Bi0.1Sr2-xTaxCa0.9Y0.1Cu2O7 (x = 0 - 0.40) series showed that the best superconducting behavior occurred at x = 0.05 with Tconset of 96 K and Tczero of 65 K. Higher Ta substitution caused gradual deterioration of superconductivity, accompanied by a change of normal state behavior from metallic to semiconductor-like behavior with increasing Ta. SEM investigation showed changes in grain size with Ta substitution. Results of electrical measurements on Tl0.9Bi0.1Sr1.95Ta0.05Ca0.9Y0.1Cu2O7 + yMgO (y = 0 - 0.8 wt.%) series superconductor revealed the highest transport critical current density Jc (at 20 K) of28 A/cm2 at y = 0.2 wt.%. Samples withy = 0 - 0.40 wt.% showed a rapid drop of Jc at low fields (< 0.1 Tesla) before a slower deterioration at higher fields (> 0.1 Tesla). This indicates the presence of weak links at low fields and dominance of strong links at higher fields. The smallest drop of Jc was observed for sample y = 0.2 wt.%. SEM results for these series showed no significant difference in microstructure between MgO added samples. Results of electrical measurements on Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 + zMgO (z = 0 - 0.80 wt.%) series revealed the highest Jc (at 30 K) of 16 A/cm2 for z = 0.1 wt.%. The behavior of Jc in external fields also indicates presence of weak links at low fields. The smallest drop of Jc was observed for z = 0.1 wt.%. SEM micrographs of MgO added samples showed smaller grain size compared to pure samples. The enhanced Jc at y = 0.2 wt.% for the Tl0.9Bi0.1Sr1.9Ta0.05Ca0.9Y0.1Cu2O7 +yMgO series and z = 0.1 wt.% for the Tl0.5Pb0.5Sr1.8Yb0.2CaCu2O7 + zMgO series is suggested to be due to flux pinning as a result of the MgO additions. In conclusion, substitution of Ta0.05 at Sr-site successfully stabilized the 1212-phase during synthesis of T11212 superconductors. The addition of a moderate amount of nano-MgO particle before final sintering improved transport critical current density and enhanced flux pinning ability of the Tl-1212 superconductors. 2008 Thesis NonPeerReviewed text en https://ir.uitm.edu.my/id/eprint/27693/1/TM_ZULZAMRI%20SALLEH%20AS%2008_5.pdf Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh. (2008) Masters thesis, thesis, Universiti Teknologi MARA. <http://terminalib.uitm.edu.my/27693.pdf> |
| spellingShingle | Electricity Salleh, Zulzamri Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh |
| title | Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh |
| title_full | Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh |
| title_fullStr | Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh |
| title_full_unstemmed | Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh |
| title_short | Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh |
| title_sort | effects of ta substitution and addition of nano mgo particles on formation and superconductivity of tlsr1212 ceramics zulzamri salleh |
| topic | Electricity |
| url | https://ir.uitm.edu.my/id/eprint/27693/1/TM_ZULZAMRI%20SALLEH%20AS%2008_5.pdf |
| work_keys_str_mv | AT sallehzulzamri effectsoftasubstitutionandadditionofnanomgoparticlesonformationandsuperconductivityoftlsr1212ceramicszulzamrisalleh |