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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Main Author:	Salleh, Zulzamri
Format:	Thesis
Language:	English
Published:	2008
Subjects:	Electricity
Online Access:	https://ir.uitm.edu.my/id/eprint/27693/1/TM_ZULZAMRI%20SALLEH%20AS%2008_5.pdf
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spelling	my-uitm-ir.276932020-02-05T07:21:32Z Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh 2008 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 https://ir.uitm.edu.my/id/eprint/27693/ https://ir.uitm.edu.my/id/eprint/27693/1/TM_ZULZAMRI%20SALLEH%20AS%2008_5.pdf text en public masters Universiti Teknologi MARA Faculty of Applied Sciences
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
topic	Electricity
spellingShingle	Electricity Salleh, Zulzamri Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh
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.
format	Thesis
qualification_level	Master's degree
author	Salleh, Zulzamri
author_facet	Salleh, Zulzamri
author_sort	Salleh, Zulzamri
title	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_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_sort	effects of ta substitution and addition of nano-mgo particles on formation and superconductivity of tlsr1212 ceramics / zulzamri salleh
granting_institution	Universiti Teknologi MARA
granting_department	Faculty of Applied Sciences
publishDate	2008
url	https://ir.uitm.edu.my/id/eprint/27693/1/TM_ZULZAMRI%20SALLEH%20AS%2008_5.pdf
_version_	1783733994719805440

Effects of Ta substitution and addition of nano-MgO particles on formation and superconductivity of TlSr1212 ceramics / Zulzamri Salleh

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