Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This thesis presents an attempt at creating a fully functional SQUID for the purposes
of a predefined application. The goal of the work is to provide a method
of development, primarily utilising the facilities of the Engineering Faculty of the
University of Stellenbosch, with minimal assistance from other departments. This
method is then analysed and the successes and failures discussed in order to provide
guidelines and recommendations for future research.
The device consists of a gradiometric SQUID, as well as electronics which provide
the SQUID bias current, output linearisation and output signal filtering. YBCO
is used for the superconducting material, allowing the use of liquid nitrogen as
coolant which eases the operation and portability of the device. Various methods
of creating Josephson junctions are tested, such as constriction bridges using AFM
lithography and step-edge junctions, with and without different buffer layers.
Proof of concept simulations demonstrate the viability of the device. Unfortunately,
a functional device could not be constructed, mostly due to the design
requiring higher levels of resolution and process control than some of the available
facilities can provide. Recommendations are provided for future researchers. / AFRIKAANSE OPSOMMING: Hierdie tesis beskryf ’n poging om ’n volledige funksionele SQUID te vervaardig
vir die doeleindes van ’n vasgestelde toepassing. Die doel van die werk is om
’n metode te voorsien wat hoofsaaklik gebruik maak van die fasiliteite van die
Ingenieurswese Fakulteit van die Universiteit van Stellenbosch, met minimale hulp
van ander departemente. Hierdie metode word dan ondersoek en die suksesse
en mislukkings bespreek om riglyne en voorstellings te voorsien vir toekomstige
navorsing.
Die toestel bestaan uit ’n gradiometriese SQUID, sowel as elektronika wat voorsiening
maak vir voorspanning, uittree-linearisering en ’n uittree-filter. YBCO is as
supergeleidende materiaal gebruik, wat die gebruik van vloeibare stikstof as verkoeler
moontlik maak en dus die hantering en draagbaarheid van die toestel vergemaklik.
Verskillende metodes om Josephson-vlakke te vervaardig is getoets, onder
andere vernouingsbrugvlakke deur middel van AFM litografie en stapvlakke met
en sonder bufferlae.
Bewys van konsep simulasies demonstreer die lewensvatbaarheid van die toestel.
Ongelukkig kon ’n funksionele weergawe van die toestel nie vervaardig word
nie, hoofsaaklik as gevolg van die ontwerp wat hoër resolusievlakke en beter prosesbeheer
benodig as wat sekere van die beskikbare fasiliteite kan voorsien. Aanbevelings
word voorsien vir toekomstige navorsers.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/4378 |
| Date | 03 1900 |
| Creators | Muller, Benjamin John Frederick |
| Contributors | Perold, W. J., University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 97 p. : ill. |
| Rights | University of Stellenbosch |
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