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[{"key": "dc.contributor.advisor", "value": "Maasilta, Ilari", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Valkiala, Ville", "language": null, "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2015-12-17T13:47:39Z", "language": "", "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2015-12-17T13:47:39Z", "language": "", "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2015", "language": null, "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.other", "value": "oai:jykdok.linneanet.fi:1506168", "language": null, "element": "identifier", "qualifier": "other", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/48178", "language": "", "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Ty\u00f6n aiheena on pinta-alaltaan suuret SINIS-tunneliliitokset ja niiden k\u00e4ytt\u00f6 j\u00e4\u00e4hdytyksess\u00e4. SINIS-tunneliliitos koostuu kahdesta normaalimetalli-eristesuprajohde (NIS) rakenteesta, jotka ovat kytkettyn\u00e4 toisiinsa sarjaankytkenn\u00e4ll\u00e4. T\u00e4llaisia rakenteita voidaan k\u00e4ytt\u00e4\u00e4 j\u00e4\u00e4hdytyksess\u00e4 matalissa l\u00e4mp\u00f6tiloissa.\r\nT\u00e4m\u00e4n mahdollistaa suprajohteille ominainen energia-aukko, joka tarkoittaa, ett\u00e4 tietyill\u00e4 energian arvoilla suprajohteessa ei ole sallittuja tiloja, joille elektronit voisivat asettua. Energia-aukko sijoittuu keskitetysti Fermi-energian E_F kohtaan, joka tarkoittaa ett\u00e4 l\u00e4mp\u00f6tilassa T = 0 kaikki Fermi-energian alapuolella olevat tilat ovat miehitettyj\u00e4 ja sen yl\u00e4puolella olevat tyhjill\u00e4\u00e4n. Kun normaalimetallin ja suprajohteen v\u00e4lille kytket\u00e4\u00e4n j\u00e4nnite, metallien Fermi-tasoja voidaan muuttaa, ja elektronit pystyv\u00e4t tunneloitumaan normaalimetallista suprajohteeseen. Sopivalla j\u00e4nnitteen arvolla vain korkeimman energian omaavat elektronit normaalimetallissa ovat energiassa suprajohteen energia-aukon yl\u00e4puolella, joten vain ne pystyv\u00e4t tunneloitumaan. T\u00e4m\u00e4 pienent\u00e4\u00e4 normaalimetallin keskim\u00e4\u00e4r\u00e4ist\u00e4 energiaa, joten sen l\u00e4mp\u00f6tila laskee.\r\n\r\nSINIS-tunneliliitoksen j\u00e4\u00e4hdytysteho on verrannollinen liitoksen pintaalaan ja energia-aukon neli\u00f6juureen. T\u00e4m\u00e4n takia j\u00e4\u00e4hdytystehoa saadaan teorian mukaan kasvatettua k\u00e4ytt\u00e4m\u00e4ll\u00e4 mahdollisimman suuria liitospintaaloja ja suprajohdemateriaaleja, joilla on mahdollisimman suuri energiaaukko.\r\n\r\nT\u00e4ss\u00e4 ty\u00f6ss\u00e4 valmistettiin 60 \u00b5m x 60 \u00b5m ja 30 \u00b5m x 30 \u00b5m Al/AlOx/Cu SINIS liitoksia ja mitattiin niiden virta-j\u00e4nnite k\u00e4ytt\u00e4ytymist\u00e4 matalissa l\u00e4mp\u00f6tiloissa. Alumiinin lis\u00e4ksi my\u00f6s niobia kokeiltiin suprajohdemateriaalina, koska sill\u00e4 on alkuainesuprajohteista suurin energia-aukko. Tulokset osoittavat, ett\u00e4 valmiiden n\u00e4ytteiden k\u00e4ytt\u00e4ytyminen eroaa ideaalisesta teorian mukaisesta k\u00e4ytt\u00e4ytymisest\u00e4, mutta siin\u00e4 on kuitenkin selv\u00e4sti n\u00e4ht\u00e4viss\u00e4 tyypillisi\u00e4 tunneliliitoksille ominaisia piirteit\u00e4.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "NIS tunnel junctions are small-scale structures consisting of a superconductor and a normal metal separated by a thin insulating barrier. They can be used in cooling applications at ultra low temperatures. A SINIS junction contains two NIS junctions in series. The cooling power of the device is proportional to the area of the junction and the energy gap of the superconductor.\r\nIn this work large-area Al/AlOx/Cu junctions were fabricated with standard lithographic techniques and ultra high vacuum evaporation. The areas of the junctions are 60 \u00b5m x 60 \u00b5m and 30 \u00b5m x 30 \u00b5m. Current-voltage characteristics of the devices were measured at millikelvin temperature range using 3He-4He-dilution refrigerator. The obtained IV and dI/dV data deviates from ideal BCS behavior, but still shows some typical tunnel junction characteristics. In addition to aluminum, Nb/Al/AlOx/Cu junctions with niobium as the superconducting electrode were also fabricated. Nb is the element with the highest energy gap, making it theoretically ideal material for SINIS cooler fabrication.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted using Plone Publishing form by Ville Valkiala (vipevalk) on 2015-12-17 13:47:38.657607. Form: Pro gradu -lomake (https://kirjasto.jyu.fi/julkaisut/julkaisulomakkeet/pro-gradu-lomake). JyX data: [jyx_publishing-allowed (fi) =True]", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by jyx lomake-julkaisija (jyx-julkaisija.group@korppi.jyu.fi) on 2015-12-17T13:47:39Z\r\nNo. of bitstreams: 2\r\nURN:NBN:fi:jyu-201512174095.pdf: 2651925 bytes, checksum: 0f0d6274321b8b0a05edbce8423e1f3e (MD5)\r\nlicense.html: 4817 bytes, checksum: 30db68f1f589f2beb3f1d0ec656a4bf0 (MD5)", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2015-12-17T13:47:39Z (GMT). No. of bitstreams: 2\r\nURN:NBN:fi:jyu-201512174095.pdf: 2651925 bytes, checksum: 0f0d6274321b8b0a05edbce8423e1f3e (MD5)\r\nlicense.html: 4817 bytes, checksum: 30db68f1f589f2beb3f1d0ec656a4bf0 (MD5)\r\n Previous issue date: 2015", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "1 verkkoaineisto (63 sivua)", "language": null, "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.format.mimetype", "value": "application/pdf", "language": null, "element": "format", "qualifier": "mimetype", "schema": "dc"}, {"key": "dc.language.iso", "value": "eng", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": "en", "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "tunneliliitokset", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "Large-area SINIS tunnel junctions for cooling applications", "language": null, "element": "title", "qualifier": null, "schema": "dc"}, {"key": "dc.type", "value": "master thesis", "language": null, "element": "type", "qualifier": null, "schema": "dc"}, {"key": "dc.identifier.urn", "value": "URN:NBN:fi:jyu-201512174095", "language": null, "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Pro gradu -tutkielma", "language": "fi", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Master\u2019s thesis", "language": "en", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Matemaattis-luonnontieteellinen tiedekunta", "language": "fi", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Faculty of Sciences", "language": "en", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Fysiikan laitos", "language": "fi", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Department of Physics", "language": "en", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": "en", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "Jyv\u00e4skyl\u00e4n yliopisto", "language": "fi", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Soveltava fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Applied Physics", "language": "en", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.date.updated", "value": "2015-12-17T13:47:40Z", "language": "", "element": "date", "qualifier": "updated", "schema": "dc"}, {"key": "yvv.contractresearch.funding", "value": "0", "language": "", "element": "contractresearch", "qualifier": "funding", "schema": "yvv"}, {"key": "dc.type.coar", "value": "http://purl.org/coar/resource_type/c_bdcc", "language": null, "element": "type", "qualifier": "coar", "schema": "dc"}, {"key": "dc.rights.accesslevel", "value": "openAccess", "language": "fi", "element": "rights", "qualifier": "accesslevel", "schema": "dc"}, {"key": "dc.type.publication", "value": "masterThesis", "language": null, "element": "type", "qualifier": "publication", "schema": "dc"}, {"key": "dc.subject.oppiainekoodi", "value": "4023", "language": null, "element": "subject", "qualifier": "oppiainekoodi", "schema": "dc"}, {"key": "dc.subject.yso", "value": "j\u00e4\u00e4hdytys", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "suprajohtavuus", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.format.content", "value": "fulltext", "language": null, "element": "format", "qualifier": "content", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}, {"key": "dc.type.okm", "value": "G2", "language": null, "element": "type", "qualifier": "okm", "schema": "dc"}]
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