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Techniques for enhancing the PLD growth of superconducting YBCO thin films
Thesis (MEng)--Stellenbosch University, 2014.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2015
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| _version_ | 1867613902335901696 |
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| access_status_str | Open Access |
| author | Hardie, Graham Lyall |
| author2 | Perold, Willem |
| author_browse | Hardie, Graham Lyall Perold, Willem |
| author_facet | Perold, Willem Hardie, Graham Lyall |
| author_sort | Hardie, Graham Lyall |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2014. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/96096 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:31.605Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/96096 Techniques for enhancing the PLD growth of superconducting YBCO thin films Hardie, Graham Lyall Perold, Willem Stellenbosch University. Faculty of Engineering. Department of Electrical and Electronic Engineering. High Temperature Superconductors Thin films Superconductivity Pulsed laser deposition Theses -- Electrical engineering Dissertations -- Electrical engineering UCTD Thesis (MEng)--Stellenbosch University, 2014. ENGLISH ABSTRACT: High Temperature Superconductors (HTS) exhibit exceptional electrical properties that make them attractive candidates for numerous electronic devices and applications. However, constructing working devices can be challenging due to fabrication difficulties of these brittle ceramics. This thesis investigates new methods to make the fabrication of high quality YBa2Cu3O7 (YBCO) thin films easier and compatible with more materials. We present the development of a universal add-on method that can be used in situ to improve the quality of superconducting thin films deposited by Pulsed Laser deposition (PLD). We investigate the in situ application of electric fields and voltage biasing to improve the thin film growth. Considering various electrode configurations, we have developed a final electrode design that is stable and produces reproducible results. By introducing an insulated high voltage (HV) electrode into the chamber during deposition, the quality of the deposited thin films can be modulated depending on the polarity of the voltage applied. Applying a positive voltage improves the film quality obtained. Applying a negative voltage degrades the superconducting properties of the films. A simple proof-of-concept HTS dual-mode microwave filter was designed, fabricated and tested. Only the filter produced using our novel PLD technique displayed the correct filtering action upon cooling to 77K. This is attributed to the thin films better superconducting properties due to our developed technique. AFRIKAANSE OPSOMMING: Hoë Temperatuur Supergeleiers (HTS) vertoon aantreklike elektriese eienskappe wat hulle goeie kandidate maak vir verskeie elektroniese toepassings. Om werkende toestelle te ontwikkel kan 'n uitdaging wees, as gevolg van die vervaardigings probleme wat bestaan vir hierdie bros keramiek materiaal. Hierdie tesis ondersoek nuwe metodes om die vervaardiging van 'n hoë gehalte YBa2Cu3O7 (YBCO) dun films makliker en versoenbaar te maak met verskeie materiale. Ons toon die ontwikkeling van 'n algemene metode wat maklik bygevoeg kan word om in situ die gehalte van supergeleidende dun films, wat deur gepulseerde laser deponering (PLD) gedeponeer is, te verbeter. Ons ondersoek die in situ toepassing van elektriese velde en spannings om die dun film groei te verbeter. Verder oorweeg ons verskeie elektrode konfigurasies en ontwikkel 'n finale elektrode ontwerp wat stabiel is en herhaalbare resultate produseer. Die kwaliteit van die gedeponeerde dun films kan gemoduleer word deur die byvoeging van 'n geïsoleerde hoogspannings (HV) elektrode tydens deponering, afhangende van die polariteit van die aangelegde spanning. 'n Positiewe spanning verhoog die film kwaliteit, terwyl 'n negatiewe spanning die supergeleidende eienskappe van die films verlaag. 'n Eenvoudige HTS dubbele-modus mikrogolffilter is ontwerp, vervaardig en getoets, om as toepassings voorbeeld te dien. Slegs die filter wat geproduseer was met behulp van ons nuwe PLD tegniek, vertoon die beste filter oordrag by 77K. Dit word toegeskryf aan die beter supergeleidende eienskappe van die dun film, as gevolg van die toepassing van ons ontwikkelde tegniek. 2015-01-13T11:50:21Z 2015-01-13T11:50:21Z 2014-12 Thesis http://hdl.handle.net/10019.1/96096 en_ZA Stellenbosch University xviii, 137 p. : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | High Temperature Superconductors Thin films Superconductivity Pulsed laser deposition Theses -- Electrical engineering Dissertations -- Electrical engineering UCTD Hardie, Graham Lyall Techniques for enhancing the PLD growth of superconducting YBCO thin films |
| title | Techniques for enhancing the PLD growth of superconducting YBCO thin films |
| title_full | Techniques for enhancing the PLD growth of superconducting YBCO thin films |
| title_fullStr | Techniques for enhancing the PLD growth of superconducting YBCO thin films |
| title_full_unstemmed | Techniques for enhancing the PLD growth of superconducting YBCO thin films |
| title_short | Techniques for enhancing the PLD growth of superconducting YBCO thin films |
| title_sort | techniques for enhancing the pld growth of superconducting ybco thin films |
| topic | High Temperature Superconductors Thin films Superconductivity Pulsed laser deposition Theses -- Electrical engineering Dissertations -- Electrical engineering UCTD |
| url | http://hdl.handle.net/10019.1/96096 |
| work_keys_str_mv | AT hardiegrahamlyall techniquesforenhancingthepldgrowthofsuperconductingybcothinfilms |