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[{"key": "dc.contributor.advisor", "value": "Maasilta, Ilari", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Ruhtinas, Aki", "language": "", "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2020-07-28T07:08:40Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2020-07-28T07:08:40Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2020", "language": "", "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/71261", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Vuonna 2015 Cybart et al. osoittivat ett\u00e4 Josephsonin liitoksia voi tehd\u00e4 kuvioimalla\nsuoraan heliumionisuihkulla YBCO ohutkalvoja. T\u00e4m\u00e4 menetelm\u00e4 on\nhyvin lupaava, sill\u00e4 se voisi mahdollistaa Josephsonin liitosten valmistamisen\naikaisempaa yksinkertaisemmalla menetelm\u00e4ll\u00e4. Lis\u00e4ksi t\u00e4t\u00e4 menetelm\u00e4\u00e4 voisi\nmahdollisesti k\u00e4ytt\u00e4\u00e4 suprajohde-eriste transition tutkimiseeen.\n\nT\u00e4ss\u00e4 tutkielmassa fokusoitua heliumionisuihkua k\u00e4ytet\u00e4\u00e4n tuottamaan ep\u00e4j\u00e4rjestyst\u00e4\nnitridiohutkalvoihin ja n\u00e4in lokaalisti kontrolloimaan suprajohde-eristetransitiota\nt\u00e4ll\u00e4 alueella. T\u00e4m\u00e4n menetelm\u00e4n osoitetaan soveltuvan Josephsonin\nliitosten tekemiseen suprajohtavissa nitrideiss\u00e4. T\u00e4ss\u00e4 ty\u00f6ss\u00e4 k\u00e4ytetyt\nsuprajohtavat TiN, NbN ja NbTiN ohutkalvot kasvatetaan pulssilaserkasvatuksella(\nPLD), ja huomionarvoista on ett\u00e4 t\u00e4m\u00e4 on ilmeisesti ensimm\u00e4inen kerta\nkun NbTiN ohutkalvoja kasvatetaan PLD:n avulla. T\u00e4m\u00e4n projektin aikana PLDlaitteistoa\nparanneltiin, ja n\u00e4m\u00e4 muutokset k\u00e4yd\u00e4\u00e4n l\u00e4pi t\u00e4ss\u00e4 tutkielmassa.\n\nValmistetut n\u00e4ytteet karakterisoitiin matalan l\u00e4mp\u00f6tilan mittausten avulla.\nKaikissa tutkituissa nitrideiss\u00e4 suprajohtavaa kriittist\u00e4 l\u00e4mp\u00f6tilaa voitiin laskea\nheliumionisuihkun avulla, ja lasku oli sit\u00e4 suurempi mit\u00e4 isompi annos heliumionisuihkua\nmateriaaliin kohdistettiin. T\u00e4ss\u00e4 ty\u00f6ss\u00e4 osoitetaan ett\u00e4 t\u00e4t\u00e4 kontroilloitua\nTc:n laskua voidaan k\u00e4ytt\u00e4\u00e4 SNS-tyyppisten Josephsonin liitosten valmistamiseen,\njolloin heikon linkin ominaisuuksia voidaan s\u00e4\u00e4t\u00e4\u00e4 hyvin paljon.\n\nNbTiN osoittautui kaikista lupaavimmaksi materiaaliksi, koska sill\u00e4 on korkea\nTc (15.3 K) ja pieni resistiivisyys. Lis\u00e4ksi t\u00e4ss\u00e4 tutkielmassa osoitetaan ett\u00e4 NbTiN\nvoidaan saada erist\u00e4v\u00e4ksi kohdistamalla siihen tarpeeksi suuri annos heliumioneja,\njolloin my\u00f6s SIS-tyypin liitoksia voidaan tehd\u00e4. SIS-liitoksia voitiin tehd\u00e4\nonnistuneesti, mutta kaikissa selv\u00e4sti erist\u00e4viss\u00e4 n\u00e4ytteiss\u00e4 kriittinen virta oli\nsuppressoitu.\n\nAikaisemmin ei ole raportoitu Josephsonin liitosten valmistamista nitrideiss\u00e4\nsuorakirjoittamisen avulla, ja t\u00e4m\u00e4 ty\u00f6 voikin avata uusia mahdollisuuksia\nJosephsonin liitosten valmistukseseen tulevaisuudessa. Sopiva lyhenne t\u00e4ll\u00e4iselle\nuudelle Josephsonin liitokselle voisi olla mahdollisesti \"Ep\u00e4j\u00e4rjestyneen heikon\nlinkin Josephsonin liitos\" eli dJJ.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Direct writing of Josephson junctions using focused ion beam in YBCO thin films\nwas demonstrated by Cybart et al. in 2015. This method could possibly simplify\nthe fabrication of Josephson junctions for superconducting devices as well as\nprovide versatile tool to investigate the physics of disorder-driven superconductorinsulator\ntransition (SIT).\n\nIn this thesis this method is used to locally control the SIT in superconducting\nnitride thin films via disorder induced by the helium ion beam, and we demonstrate\nhow this can be used in Josephson junction fabrication. Here high quality\nsuperconducting thin films of NbN, TiN and NbTiN grown with an infrared\npulsed laser deposition (PLD) technique are used for the device fabrication. To our\nknowledge, this is the first time when superconducting niobium titanium nitride\nis deposited with pulsed laser deposition. During this project some modifications\nand improvements to the PLD setup were made, and they are briefly discussed in\nthe thesis.\n\nLow temperature measurements of the fabricated samples revealed that in\nall of the studied nitrides superconductivity can be suppressed by helium ion\nirradiation, with higher helium ion fluence resulting in a lower critical temperature\nTc. This controllable Tc suppression combined with the high spatial resolution of\nthe helium ion microscope was proven to enable successful fabrication of SNS-type\nJosephson junctions with highly tunable weak links.\n\nMost promising candidate among the three superconducting nitrides seems\nto be NbTiN, because of its high Tc (15.3 K) and low resistivity. In addition,\nwe demonstrate that NbTiN thin films can be pushed to the insulating side of\nthe SIT with a high enough helium ion fluence. Thus, fabrication of insulating\nbarrier SIS Josephson junctions was also shown to be possible. However, in all of\nthe fabricated devices exhibiting clear insulating behaviour, critical current was\nsuppressed.\n\nFabrication of Josephson junctions with direct writing has not been previously\nreported on conventional low temperature superconductors, and this work could\nopen up new exciting possibilities in Josephson junction fabrication in the future.\nSuitable acronym for this new kind of device could be Disordered weak link\nJosephson Junction (dJJ).", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Paivi Vuorio (paelvuor@jyu.fi) on 2020-07-28T07:08:40Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2020-07-28T07:08:40Z (GMT). No. of bitstreams: 0\n Previous issue date: 2020", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "144", "language": "", "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": "disorder", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "nitride", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "superconductor-insulator transition", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "Josephson junction", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "helium ion beam", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "Direct writing of Josephson junctions in superconducting nitrides with focused helium ion beam", "language": "", "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-202007285410", "language": "", "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": "Jyv\u00e4skyl\u00e4n yliopisto", "language": "fi", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": "en", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Physics", "language": "en", "element": "subject", "qualifier": "discipline", "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": null, "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": "4021", "language": "", "element": "subject", "qualifier": "oppiainekoodi", "schema": "dc"}, {"key": "dc.subject.yso", "value": "suprajohtavuus", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "ohutkalvot", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "superconductivity", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "thin films", "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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