{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/98326"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/98326","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Imaging vortex dynamics in Josephson arrays using magnetic force microscopy","abstract":"Vortices and vortex lattices play a major role in determining the transport properties of type-II superconductors[1–3], and enable a platform to investigate exotic superconducting physics[4,5]. The study of vortex matter has generally focused on novel states in 2D ﬁlms and structures, and has recently moved to investigating systems with constrained dimensions and smaller vortex numbers[6–11]. Vortices are responsible, for example, for some electrical transport regimes in superconducting ﬁlms, as well as the Berezinkskii-Kosterlitz-Thouless phase transition in superconducting ﬁlms[12]. Unconventional forms of superconductivity, such as the spin triplet pairing predicted in Sr2RuO4, or in topological insulators paired to s-wave superconductors, contain two condensates that may support two vortex lattices, and may display Majorana modes, signatures of which may have been seen in other superconducting systems[13–17]. The vortex-vortex interactions, or inter and intra-condensate couplings in multicondensate systems, are important parameters that characterize the behavior of the systems that display such phenomena[18–20]. In investigating these parameters, a technique that can both probe the energies in a system, as well as manipulate the vortices therein, has long been desired. In this work, we report on progress in determining the energy scales of vortex systems, as well as limited control over the vortex motion. Using a technique based on magnetic force microscopy, we can directly measure the resonant motion of vortices present in a superconducting lattice. We use a scanning magnetic tip to trap a small number of vortices in a superconducting Josephson junction array near the tip. By observing the resonant motion of the conﬁguration of vortices, a map of the location of energy degeneracies between diﬀerent stable conﬁgurations is generated. From this data, we use a simulation to extract the relative strengths of the characteristic energy scales for the system, including the vortex-magnetic ﬁeld interaction, the vortex-vortex interaction strength, and the chemical potential for the vortices. The simulations for small numbers of vortices ﬁts the data well for multiple ﬁeld proﬁles and lattice spacings. The ability to tune the vortex number and conﬁgurations by changing the magnetic ﬁeld proﬁle from the tip, as well as the lattice parameters of the superconducting surface, are key portions of this technique. We demonstrate that the relative strengths of the chemical potential and vortex-vortex interactions can be tuned relative to the vortex-magnetic ﬁeld energy by changing the lattice spacing of the array. We also show that by moving the tip farther from or closer to the surface, which changes the potential well from the tip, that the conﬁgurations of vortices can be modiﬁed. From the experiments, we show that this technique can be used to both extract the strengths of the relative energy scales in this system and other superconducting systems, as well as for manipulating the vortex conﬁgurations for quantum computation applications.","abstract_html":"Vortices and vortex lattices play a major role in determining the transport properties of type-II superconductors[1–3], and enable a platform to investigate exotic superconducting physics[4,5]. The study of vortex matter has generally focused on novel states in 2D ﬁlms and structures, and has recently moved to investigating systems with constrained dimensions and smaller vortex numbers[6–11]. Vortices are responsible, for example, for some electrical transport regimes in superconducting ﬁlms, as well as the Berezinkskii-Kosterlitz-Thouless phase transition in superconducting ﬁlms[12]. Unconventional forms of superconductivity, such as the spin triplet pairing predicted in Sr2RuO4, or in topological insulators paired to s-wave superconductors, contain two condensates that may support two vortex lattices, and may display Majorana modes, signatures of which may have been seen in other superconducting systems[13–17]. The vortex-vortex interactions, or inter and intra-condensate couplings in multicondensate systems, are important parameters that characterize the behavior of the systems that display such phenomena[18–20]. In investigating these parameters, a technique that can both probe the energies in a system, as well as manipulate the vortices therein, has long been desired. In this work, we report on progress in determining the energy scales of vortex systems, as well as limited control over the vortex motion. Using a technique based on magnetic force microscopy, we can directly measure the resonant motion of vortices present in a superconducting lattice. We use a scanning magnetic tip to trap a small number of vortices in a superconducting Josephson junction array near the tip. By observing the resonant motion of the conﬁguration of vortices, a map of the location of energy degeneracies between diﬀerent stable conﬁgurations is generated. From this data, we use a simulation to extract the relative strengths of the characteristic energy scales for the system, including the vortex-magnetic ﬁeld interaction, the vortex-vortex interaction strength, and the chemical potential for the vortices. The simulations for small numbers of vortices ﬁts the data well for multiple ﬁeld proﬁles and lattice spacings. The ability to tune the vortex number and conﬁgurations by changing the magnetic ﬁeld proﬁle from the tip, as well as the lattice parameters of the superconducting surface, are key portions of this technique. We demonstrate that the relative strengths of the chemical potential and vortex-vortex interactions can be tuned relative to the vortex-magnetic ﬁeld energy by changing the lattice spacing of the array. We also show that by moving the tip farther from or closer to the surface, which changes the potential well from the tip, that the conﬁgurations of vortices can be modiﬁed. From the experiments, we show that this technique can be used to both extract the strengths of the relative energy scales in this system and other superconducting systems, as well as for manipulating the vortex conﬁgurations for quantum computation applications.","abstract_has_math":false,"creators":["Naibert, Tyler R."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Budakian, Raffi","Van Harlingen, Dale","Vishveshwara, Smitha","Gadway, Bryce"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017-09-29T17:56:21Z","date_published":"2017-09-29T17:56:21Z","updated_at":"2026-07-22T22:24:35Z","subjects":["Magnetic force microscopy","Superconductor","Superconductivity","Vortex","Josephson junction","Josephson junction array (JJA)","Superconductor-normal metal-superconductor (SNS) array","Vortex interactions","Pinning"],"languages":["en"],"rights":["Copyright 2017 Tyler R. Naibert"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/98326","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Budakian, Raffi","Van Harlingen, Dale","Vishveshwara, Smitha","Gadway, Bryce"]},{"key":"dc:creator","label":"Author","values":["Naibert, Tyler R."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017-09-29T17:56:21Z","2017-07-03","2017-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Magnetic force microscopy","Superconductor","Superconductivity","Vortex","Josephson junction","Josephson junction array (JJA)","Superconductor-normal metal-superconductor (SNS) array","Vortex interactions","Pinning"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2017 Tyler R. Naibert"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/98326"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Vortices and vortex lattices play a major role in determining the transport properties of type-II superconductors[1–3], and enable a platform to investigate exotic superconducting physics[4,5]. The study of vortex matter has generally focused on novel states in 2D ﬁlms and structures, and has recently moved to investigating systems with constrained dimensions and smaller vortex numbers[6–11]. Vortices are responsible, for example, for some electrical transport regimes in superconducting ﬁlms, as well as the Berezinkskii-Kosterlitz-Thouless phase transition in superconducting ﬁlms[12]. Unconventional forms of superconductivity, such as the spin triplet pairing predicted in Sr2RuO4, or in topological insulators paired to s-wave superconductors, contain two condensates that may support two vortex lattices, and may display Majorana modes, signatures of which may have been seen in other superconducting systems[13–17]. The vortex-vortex interactions, or inter and intra-condensate couplings in multicondensate systems, are important parameters that characterize the behavior of the systems that display such phenomena[18–20]. In investigating these parameters, a technique that can both probe the energies in a system, as well as manipulate the vortices therein, has long been desired. In this work, we report on progress in determining the energy scales of vortex systems, as well as limited control over the vortex motion. Using a technique based on magnetic force microscopy, we can directly measure the resonant motion of vortices present in a superconducting lattice. We use a scanning magnetic tip to trap a small number of vortices in a superconducting Josephson junction array near the tip. By observing the resonant motion of the conﬁguration of vortices, a map of the location of energy degeneracies between diﬀerent stable conﬁgurations is generated. From this data, we use a simulation to extract the relative strengths of the characteristic energy scales for the system, including the vortex-magnetic ﬁeld interaction, the vortex-vortex interaction strength, and the chemical potential for the vortices. The simulations for small numbers of vortices ﬁts the data well for multiple ﬁeld proﬁles and lattice spacings. The ability to tune the vortex number and conﬁgurations by changing the magnetic ﬁeld proﬁle from the tip, as well as the lattice parameters of the superconducting surface, are key portions of this technique. We demonstrate that the relative strengths of the chemical potential and vortex-vortex interactions can be tuned relative to the vortex-magnetic ﬁeld energy by changing the lattice spacing of the array. We also show that by moving the tip farther from or closer to the surface, which changes the potential well from the tip, that the conﬁgurations of vortices can be modiﬁed. From the experiments, we show that this technique can be used to both extract the strengths of the relative energy scales in this system and other superconducting systems, as well as for manipulating the vortex conﬁgurations for quantum computation applications.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms","The student, Tyler Naibert, accepted the attached license on 2017-07-03 at 09:00.","The student, Tyler Naibert, submitted this Dissertation for approval on 2017-07-03 at 09:14.","This Dissertation was approved for publication on 2017-07-03 at 16:23.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11300 on 2017-09-29 at 11:27:42","Made available in DSpace on 2017-09-29T17:56:21Z (GMT). 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The study of vortex matter has generally focused on novel states in 2D ﬁlms and structures, and has recently moved to investigating systems with constrained dimensions and smaller vortex numbers[6–11]. Vortices are responsible, for example, for some electrical transport regimes in superconducting ﬁlms, as well as the Berezinkskii-Kosterlitz-Thouless phase transition in superconducting ﬁlms[12]. Unconventional forms of superconductivity, such as the spin triplet pairing predicted in Sr2RuO4, or in topological insulators paired to s-wave superconductors, contain two condensates that may support two vortex lattices, and may display Majorana modes, signatures of which may have been seen in other superconducting systems[13–17]. The vortex-vortex interactions, or inter and intra-condensate couplings in multicondensate systems, are important parameters that characterize the behavior of the systems that display such phenomena[18–20]. In investigating these parameters, a technique that can both probe the energies in a system, as well as manipulate the vortices therein, has long been desired. In this work, we report on progress in determining the energy scales of vortex systems, as well as limited control over the vortex motion. Using a technique based on magnetic force microscopy, we can directly measure the resonant motion of vortices present in a superconducting lattice. We use a scanning magnetic tip to trap a small number of vortices in a superconducting Josephson junction array near the tip. By observing the resonant motion of the conﬁguration of vortices, a map of the location of energy degeneracies between diﬀerent stable conﬁgurations is generated. From this data, we use a simulation to extract the relative strengths of the characteristic energy scales for the system, including the vortex-magnetic ﬁeld interaction, the vortex-vortex interaction strength, and the chemical potential for the vortices. The simulations for small numbers of vortices ﬁts the data well for multiple ﬁeld proﬁles and lattice spacings. The ability to tune the vortex number and conﬁgurations by changing the magnetic ﬁeld proﬁle from the tip, as well as the lattice parameters of the superconducting surface, are key portions of this technique. We demonstrate that the relative strengths of the chemical potential and vortex-vortex interactions can be tuned relative to the vortex-magnetic ﬁeld energy by changing the lattice spacing of the array. We also show that by moving the tip farther from or closer to the surface, which changes the potential well from the tip, that the conﬁgurations of vortices can be modiﬁed. From the experiments, we show that this technique can be used to both extract the strengths of the relative energy scales in this system and other superconducting systems, as well as for manipulating the vortex conﬁgurations for quantum computation applications.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms","The student, Tyler Naibert, accepted the attached license on 2017-07-03 at 09:00.","The student, Tyler Naibert, submitted this Dissertation for approval on 2017-07-03 at 09:14.","This Dissertation was approved for publication on 2017-07-03 at 16:23.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11300 on 2017-09-29 at 11:27:42","Made available in DSpace on 2017-09-29T17:56:21Z (GMT). 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Naibert"],"dc:subject":["Magnetic force microscopy","Superconductor","Superconductivity","Vortex","Josephson junction","Josephson junction array (JJA)","Superconductor-normal metal-superconductor (SNS) array","Vortex interactions","Pinning"],"dc:title":["Imaging vortex dynamics in Josephson arrays using magnetic force microscopy"],"dc:type":["text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:35Z"}