{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25694"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25694","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Critical magnetic fields of superconducting tungsten","abstract":"The thermodynamic critical field curve of a superconducting tungsten specimen with resistivity ratio 7,500 has been measured as a function of temperature down to 3 m K (1 m K - 10-3 oK). From the raw data the critical field H0 at T = 0 is found to be 1.14·1 ± .007 G, and the zero field transition temperature Tc is 15.39 + .17 mOK. The normal-state electronic specific heat parameter y, as derived from the critical field data, is 0.87 + .04 mJ/mole °K2. However, the magnetic field at the specimen is slightly altered by the nearby paramagnetic refrigerant- thermometer. An estimated correction applied to the data gives the new values Ho = 1.148 +/- .010 G, Tc = 15.37 +/- .17 moK, and gamma = 0.90 ± .06 mJ/mole °K2, which are considered to be the most probable values of these parameters for the tungsten specimen studied here. Deviation of the measured critical field from a parabolic dependence on temperature is in good agreement with the weak-coupling BCS theory. The very small calculated Ginzburg-Landau parameter (x:: 2 X 10^-3 ) and extremely large calculated coherence length (~o ~ 32u) are favorable for observation of a large supercooling effect in tungsten at temperatures well below Tc. Assuming that the ideal critical supercooling field was observed on an electropolished specimen, the experimental value for u is (2.6 ± 1.6) X 10^-3. A large and reproducible, though less than ideal, superheating effect was also observed with this same electropolished specimen.","abstract_html":"The thermodynamic critical field curve of a superconducting tungsten specimen with resistivity ratio 7,500 has been measured as a function of temperature down to 3 m K (1 m K - 10-3 oK). From the raw data the critical field H0 at T = 0 is found to be 1.14·1 ± .007 G, and the zero field transition temperature Tc is 15.39 + .17 mOK. The normal-state electronic specific heat parameter y, as derived from the critical field data, is 0.87 + .04 mJ/mole °K2. However, the magnetic field at the specimen is slightly altered by the nearby paramagnetic refrigerant- thermometer. An estimated correction applied to the data gives the new values Ho = 1.148 +/- .010 G, Tc = 15.37 +/- .17 moK, and gamma = 0.90 ± .06 mJ/mole °K2, which are considered to be the most probable values of these parameters for the tungsten specimen studied here. Deviation of the measured critical field from a parabolic dependence on temperature is in good agreement with the weak-coupling BCS theory. The very small calculated Ginzburg-Landau parameter (x:: 2 X 10^-3 ) and extremely large calculated coherence length (~o ~ 32u) are favorable for observation of a large supercooling effect in tungsten at temperatures well below Tc. Assuming that the ideal critical supercooling field was observed on an electropolished specimen, the experimental value for u is (2.6 ± 1.6) X 10^-3. A large and reproducible, though less than ideal, superheating effect was also observed with this same electropolished specimen.","abstract_has_math":false,"creators":["Black, William Carter"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Wheatley, J.C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-07-07T16:39:40Z","date_published":"2011-07-07T16:39:40Z","updated_at":"2026-07-22T22:25:26Z","subjects":["critical magnetic fields","superconducting tungsten","parabolic dependence","resistivity"],"languages":["en"],"rights":["1967 William Carter Black, Jr."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["6089205"],"render_values":[{"text":"6089205","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25694","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wheatley, J.C."]},{"key":"dc:creator","label":"Author","values":["Black, William Carter"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-07-07T16:39:40Z","10000-01-01","1967"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","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."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["critical magnetic fields","superconducting tungsten","parabolic dependence","resistivity"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1967 William Carter Black, Jr."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["6089205","http://hdl.handle.net/2142/25694"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The thermodynamic critical field curve of a superconducting tungsten specimen with resistivity ratio 7,500 has been measured as a function of temperature down to 3 m K (1 m K - 10-3 oK). From the raw data the critical field H0 at T = 0 is found to be 1.14·1 ± .007 G, and the zero field transition temperature Tc is 15.39 + .17 mOK. The normal-state electronic specific heat parameter y, as derived from the critical field data, is 0.87 + .04 mJ/mole °K2. However, the magnetic field at the specimen is slightly altered by the nearby paramagnetic refrigerant- thermometer. An estimated correction applied to the data gives the new values Ho = 1.148 +/- .010 G, Tc = 15.37 +/- .17 moK, and gamma = 0.90 ± .06 mJ/mole °K2, which are considered to be the most probable values of these parameters for the tungsten specimen studied here. Deviation of the measured critical field from a parabolic dependence on temperature is in good agreement with the weak-coupling BCS theory. The very small calculated Ginzburg-Landau parameter (x:: 2 X 10^-3 ) and extremely large calculated coherence length (~o ~ 32u) are favorable for observation of a large supercooling effect in tungsten at temperatures well below Tc. Assuming that the ideal critical supercooling field was observed on an electropolished specimen, the experimental value for u is (2.6 ± 1.6) X 10^-3. A large and reproducible, though less than ideal, superheating effect was also observed with this same electropolished specimen.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-07T16:39:40Z No. of bitstreams: 1 1967_black.pdf: 5775404 bytes, checksum: bb429ace41a681bd14da42d74e0cf6dc (MD5)","Made available in DSpace on 2011-07-07T16:39:40Z (GMT). No. of bitstreams: 1 1967_black.pdf: 5775404 bytes, checksum: bb429ace41a681bd14da42d74e0cf6dc (MD5) Previous issue date: 1967","Restriction data tranferred 2014-07-01T11:32:45-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-07T16:39:40Z Item is restricted indefinitely.","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Critical magnetic fields of superconducting tungsten"]}]}],"canonical_facts":{"dc:contributor":["Wheatley, J.C."],"dc:creator":["Black, William Carter"],"dc:date":["2011-07-07T16:39:40Z","10000-01-01","1967"],"dc:description":["The thermodynamic critical field curve of a superconducting tungsten specimen with resistivity ratio 7,500 has been measured as a function of temperature down to 3 m K (1 m K - 10-3 oK). From the raw data the critical field H0 at T = 0 is found to be 1.14·1 ± .007 G, and the zero field transition temperature Tc is 15.39 + .17 mOK. The normal-state electronic specific heat parameter y, as derived from the critical field data, is 0.87 + .04 mJ/mole °K2. However, the magnetic field at the specimen is slightly altered by the nearby paramagnetic refrigerant- thermometer. An estimated correction applied to the data gives the new values Ho = 1.148 +/- .010 G, Tc = 15.37 +/- .17 moK, and gamma = 0.90 ± .06 mJ/mole °K2, which are considered to be the most probable values of these parameters for the tungsten specimen studied here. Deviation of the measured critical field from a parabolic dependence on temperature is in good agreement with the weak-coupling BCS theory. The very small calculated Ginzburg-Landau parameter (x:: 2 X 10^-3 ) and extremely large calculated coherence length (~o ~ 32u) are favorable for observation of a large supercooling effect in tungsten at temperatures well below Tc. Assuming that the ideal critical supercooling field was observed on an electropolished specimen, the experimental value for u is (2.6 ± 1.6) X 10^-3. A large and reproducible, though less than ideal, superheating effect was also observed with this same electropolished specimen.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-07T16:39:40Z No. of bitstreams: 1 1967_black.pdf: 5775404 bytes, checksum: bb429ace41a681bd14da42d74e0cf6dc (MD5)","Made available in DSpace on 2011-07-07T16:39:40Z (GMT). No. of bitstreams: 1 1967_black.pdf: 5775404 bytes, checksum: bb429ace41a681bd14da42d74e0cf6dc (MD5) Previous issue date: 1967","Restriction data tranferred 2014-07-01T11:32:45-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-07T16:39:40Z Item is restricted indefinitely.","Thesis","U of I Only"],"dc:identifier":["6089205","http://hdl.handle.net/2142/25694"],"dc:language":["en"],"dc:rights":["1967 William Carter Black, Jr."],"dc:subject":["critical magnetic fields","superconducting tungsten","parabolic dependence","resistivity"],"dc:title":["Critical magnetic fields of superconducting tungsten"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:26Z"}