{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/80640"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/80640","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Growth, Transport, and Tunneling Spectroscopy of Y(1-X) Pr(x) Ba(2) Cu(3) O(7) Thin Films as a Function of Crystallographic Orientation","abstract":"The planar tunneling spectroscopy of superconducting, Pr-doped YBa$\\rm\\sb2Cu\\sb3O\\sb7$ thin films is reported. The tunneling conductance is studied as a function of both crystallographic orientation and Pr concentration. Tunnel junctions are fabricated on thin films grown by off-axis magnetron sputter deposition from single, stoichiometric targets. Four crystallographic orientations are grown: (100), (110), (103), and (001). Four different Pr concentrations are studied where x = 0, 0.2, 0.4, and 0.5, corresponding to zero resistance superconducting transition temperatures (T$\\rm\\sb{c}$'s) of 90 K, 70 K, 45 K, and 20 K, respectively. The superconducting and normal state properties of the thin films are comparable to those measured in single crystals, and the (110)-oriented $\\rm YBa\\sb2Cu\\sb3O\\sb7$ films exhibit T$\\rm\\sb{c}$'s that are unsurpassed for this orientation. The conductance of $\\rm Y\\sb{1-x}Pr\\sb{x}Ba\\sb2Cu\\sb3O\\sb7$/I/Pb planar tunnel junctions, where I is an insulator formed at the interface between the two materials, is measured as a function of temperature and magnetic field. The junctions are reproducible and well characterized. Tunneling is the dominant transport mechanism through the junctions, as verified by the observation of a well-defined Pb superconducting density of states. For a fixed Pr concentration, the same features are observed for (100)-, (110)-, and (103)-oriented (ab-oriented) films, and these features are qualitatively different than those measured for (001)-oriented (c-axis) films. The tunneling conductance data from ab-oriented films exhibit three important features. First, a gap-like feature is observed at an energy, eV $\\rm\\sim2.2k\\sb{B}T\\sb{c},$ that approximately scales with the T$\\rm\\sb{c}$ of the film. Second, there is a temperature and magnetic field dependent zero-bias conductance peak that disappears for the highest Pr concentration studied. Third, a conductance dip at 45 meV that is asymmetric with respect to bias is observed in undoped films. In contrast, the tunneling conductance data for c-axis films exhibit a gap-like feature at a fixed energy that is independent of T$\\rm\\sb{c}$ and a zero bias conductance dip. There is also a high bias dip in the c-axis conductance that is coincident with the energy of the dip observed in ab-oriented films. Results are compared and contrasted to predictions for a superconducting gap with $\\rm d\\sb{x}\\sp2\\sb{-y}\\sp2$ symmetry.","abstract_html":"The planar tunneling spectroscopy of superconducting, Pr-doped YBa$\\rm\\sb2Cu\\sb3O\\sb7$ thin films is reported. The tunneling conductance is studied as a function of both crystallographic orientation and Pr concentration. Tunnel junctions are fabricated on thin films grown by off-axis magnetron sputter deposition from single, stoichiometric targets. Four crystallographic orientations are grown: (100), (110), (103), and (001). Four different Pr concentrations are studied where x = 0, 0.2, 0.4, and 0.5, corresponding to zero resistance superconducting transition temperatures (T$\\rm\\sb{c}$'s) of 90 K, 70 K, 45 K, and 20 K, respectively. The superconducting and normal state properties of the thin films are comparable to those measured in single crystals, and the (110)-oriented $\\rm YBa\\sb2Cu\\sb3O\\sb7$ films exhibit T$\\rm\\sb{c}$'s that are unsurpassed for this orientation. The conductance of $\\rm Y\\sb{1-x}Pr\\sb{x}Ba\\sb2Cu\\sb3O\\sb7$/I/Pb planar tunnel junctions, where I is an insulator formed at the interface between the two materials, is measured as a function of temperature and magnetic field. The junctions are reproducible and well characterized. Tunneling is the dominant transport mechanism through the junctions, as verified by the observation of a well-defined Pb superconducting density of states. For a fixed Pr concentration, the same features are observed for (100)-, (110)-, and (103)-oriented (ab-oriented) films, and these features are qualitatively different than those measured for (001)-oriented (c-axis) films. The tunneling conductance data from ab-oriented films exhibit three important features. First, a gap-like feature is observed at an energy, eV $\\rm\\sim2.2k\\sb{B}T\\sb{c},$ that approximately scales with the T$\\rm\\sb{c}$ of the film. Second, there is a temperature and magnetic field dependent zero-bias conductance peak that disappears for the highest Pr concentration studied. Third, a conductance dip at 45 meV that is asymmetric with respect to bias is observed in undoped films. In contrast, the tunneling conductance data for c-axis films exhibit a gap-like feature at a fixed energy that is independent of T$\\rm\\sb{c}$ and a zero bias conductance dip. There is also a high bias dip in the c-axis conductance that is coincident with the energy of the dip observed in ab-oriented films. Results are compared and contrasted to predictions for a superconducting gap with $\\rm d\\sb{x}\\sp2\\sb{-y}\\sp2$ symmetry.","abstract_has_math":true,"creators":["Covington, Mark William"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Greene, Laura H."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T20:03:24Z","date_published":"2015-09-25T20:03:24Z","updated_at":"2026-07-22T22:26:14Z","subjects":["Physics, Condensed Matter"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9717266"],"render_values":[{"text":"(MiAaPQ)AAI9717266","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/80640","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Greene, Laura H."]},{"key":"dc:creator","label":"Author","values":["Covington, Mark William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T20:03:24Z","10000-01-01","1997"]},{"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":["Physics, Condensed Matter"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/80640","(MiAaPQ)AAI9717266"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The planar tunneling spectroscopy of superconducting, Pr-doped YBa$\\rm\\sb2Cu\\sb3O\\sb7$ thin films is reported. The tunneling conductance is studied as a function of both crystallographic orientation and Pr concentration. Tunnel junctions are fabricated on thin films grown by off-axis magnetron sputter deposition from single, stoichiometric targets. Four crystallographic orientations are grown: (100), (110), (103), and (001). Four different Pr concentrations are studied where x = 0, 0.2, 0.4, and 0.5, corresponding to zero resistance superconducting transition temperatures (T$\\rm\\sb{c}$'s) of 90 K, 70 K, 45 K, and 20 K, respectively. The superconducting and normal state properties of the thin films are comparable to those measured in single crystals, and the (110)-oriented $\\rm YBa\\sb2Cu\\sb3O\\sb7$ films exhibit T$\\rm\\sb{c}$'s that are unsurpassed for this orientation. The conductance of $\\rm Y\\sb{1-x}Pr\\sb{x}Ba\\sb2Cu\\sb3O\\sb7$/I/Pb planar tunnel junctions, where I is an insulator formed at the interface between the two materials, is measured as a function of temperature and magnetic field. The junctions are reproducible and well characterized. Tunneling is the dominant transport mechanism through the junctions, as verified by the observation of a well-defined Pb superconducting density of states. For a fixed Pr concentration, the same features are observed for (100)-, (110)-, and (103)-oriented (ab-oriented) films, and these features are qualitatively different than those measured for (001)-oriented (c-axis) films. The tunneling conductance data from ab-oriented films exhibit three important features. First, a gap-like feature is observed at an energy, eV $\\rm\\sim2.2k\\sb{B}T\\sb{c},$ that approximately scales with the T$\\rm\\sb{c}$ of the film. Second, there is a temperature and magnetic field dependent zero-bias conductance peak that disappears for the highest Pr concentration studied. Third, a conductance dip at 45 meV that is asymmetric with respect to bias is observed in undoped films. In contrast, the tunneling conductance data for c-axis films exhibit a gap-like feature at a fixed energy that is independent of T$\\rm\\sb{c}$ and a zero bias conductance dip. There is also a high bias dip in the c-axis conductance that is coincident with the energy of the dip observed in ab-oriented films. Results are compared and contrasted to predictions for a superconducting gap with $\\rm d\\sb{x}\\sp2\\sb{-y}\\sp2$ symmetry.","Made available in DSpace on 2015-09-25T20:03:24Z (GMT). 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The tunneling conductance is studied as a function of both crystallographic orientation and Pr concentration. Tunnel junctions are fabricated on thin films grown by off-axis magnetron sputter deposition from single, stoichiometric targets. Four crystallographic orientations are grown: (100), (110), (103), and (001). Four different Pr concentrations are studied where x = 0, 0.2, 0.4, and 0.5, corresponding to zero resistance superconducting transition temperatures (T$\\rm\\sb{c}$'s) of 90 K, 70 K, 45 K, and 20 K, respectively. The superconducting and normal state properties of the thin films are comparable to those measured in single crystals, and the (110)-oriented $\\rm YBa\\sb2Cu\\sb3O\\sb7$ films exhibit T$\\rm\\sb{c}$'s that are unsurpassed for this orientation. The conductance of $\\rm Y\\sb{1-x}Pr\\sb{x}Ba\\sb2Cu\\sb3O\\sb7$/I/Pb planar tunnel junctions, where I is an insulator formed at the interface between the two materials, is measured as a function of temperature and magnetic field. The junctions are reproducible and well characterized. Tunneling is the dominant transport mechanism through the junctions, as verified by the observation of a well-defined Pb superconducting density of states. For a fixed Pr concentration, the same features are observed for (100)-, (110)-, and (103)-oriented (ab-oriented) films, and these features are qualitatively different than those measured for (001)-oriented (c-axis) films. The tunneling conductance data from ab-oriented films exhibit three important features. First, a gap-like feature is observed at an energy, eV $\\rm\\sim2.2k\\sb{B}T\\sb{c},$ that approximately scales with the T$\\rm\\sb{c}$ of the film. Second, there is a temperature and magnetic field dependent zero-bias conductance peak that disappears for the highest Pr concentration studied. Third, a conductance dip at 45 meV that is asymmetric with respect to bias is observed in undoped films. In contrast, the tunneling conductance data for c-axis films exhibit a gap-like feature at a fixed energy that is independent of T$\\rm\\sb{c}$ and a zero bias conductance dip. There is also a high bias dip in the c-axis conductance that is coincident with the energy of the dip observed in ab-oriented films. Results are compared and contrasted to predictions for a superconducting gap with $\\rm d\\sb{x}\\sp2\\sb{-y}\\sp2$ symmetry.","Made available in DSpace on 2015-09-25T20:03:24Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9717266.pdf: 8208698 bytes, checksum: a1ef321678434e6e10f996b8c056d81e (MD5) Previous issue date: 1997","Embargo set by: Seth Robbins for item 81922 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","169 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997."],"dc:identifier":["http://hdl.handle.net/2142/80640","(MiAaPQ)AAI9717266"],"dc:language":["eng"],"dc:subject":["Physics, Condensed Matter"],"dc:title":["Growth, Transport, and Tunneling Spectroscopy of Y(1-X) Pr(x) Ba(2) Cu(3) O(7) Thin Films as a Function of Crystallographic Orientation"],"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":"2026-07-22T22:26:14Z"}