\"The Ba2YCu3O7-x system was investigated using thermogravimetric, thermopower, and d.c. electrical conductivity techniques. The system was found to exhibit a semiconductor to metallic transition coincident with the documented orthorhombic to tetragonal phase transition. Conduction is accomplished in the semiconducting phase by an activated small hopping polaron mechanism. The oxide was observed to be a p-type semiconductor over the temperature and oxygen activity ranges studied.
The conductivity, carrier concentration, and mobility behaviors of the oxide are primarily functions of its oxygen content. All three properties exhibited only a slight temperature dependence. The carrier concentration is essentially constant at a given oxygen content. The carrier concentration ranged from about 0.5 x 1021/cm3 at 800°C and O = 6.3 to 6 x 1021/cm3 at 500°C and O = 6.95. Mobilities ranged from about 0.05 cm2/V sec. at 600°C and O = 6.4 to 0.5 at 800°C and O = 6.7\"--Abstract, page ii.
","abstract_html":"<p>"The Ba<sub>2</sub>YCu<sub>3</sub>O<sub>7-x</sub> system was investigated using thermogravimetric, thermopower, and d.c. electrical conductivity techniques. The system was found to exhibit a semiconductor to metallic transition coincident with the documented orthorhombic to tetragonal phase transition. Conduction is accomplished in the semiconducting phase by an activated small hopping polaron mechanism. The oxide was observed to be a p-type semiconductor over the temperature and oxygen activity ranges studied.</p> <p>The conductivity, carrier concentration, and mobility behaviors of the oxide are primarily functions of its oxygen content. All three properties exhibited only a slight temperature dependence. The carrier concentration is essentially constant at a given oxygen content. The carrier concentration ranged from about 0.5 x 10<sup>21</sup>/cm<sup>3</sup> at 800°C and O = 6.3 to 6 x 10<sup>21</sup>/cm<sup>3</sup> at 500°C and O = 6.95. Mobilities ranged from about 0.05 cm<sup>2</sup>/V sec. at 600°C and O = 6.4 to 0.5 at 800°C and O = 6.7"--Abstract, page ii.</p>","abstract_has_math":false,"creators":["Brannon, C. John"],"institution":"University of Missouri--Rolla","degree_name":"Ph. D. in Ceramic Engineering","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-02-10T08:00:00Z","date_published":"2016-02-10T08:00:00Z","updated_at":"2026-07-24T03:18:50Z","subjects":["Ceramic Materials"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/714","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Brannon, C. John"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-10T08:00:00Z"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation - Restricted Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D. in Ceramic Engineering"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Missouri--Rolla"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ceramic Materials"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsmine.mst.edu/doctoral_dissertations/714"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["\"The Ba2YCu3O7-x system was investigated using thermogravimetric, thermopower, and d.c. electrical conductivity techniques. The system was found to exhibit a semiconductor to metallic transition coincident with the documented orthorhombic to tetragonal phase transition. Conduction is accomplished in the semiconducting phase by an activated small hopping polaron mechanism. The oxide was observed to be a p-type semiconductor over the temperature and oxygen activity ranges studied.
The conductivity, carrier concentration, and mobility behaviors of the oxide are primarily functions of its oxygen content. All three properties exhibited only a slight temperature dependence. The carrier concentration is essentially constant at a given oxygen content. The carrier concentration ranged from about 0.5 x 1021/cm3 at 800°C and O = 6.3 to 6 x 1021/cm3 at 500°C and O = 6.95. Mobilities ranged from about 0.05 cm2/V sec. at 600°C and O = 6.4 to 0.5 at 800°C and O = 6.7\"--Abstract, page ii.
"]},{"key":"dc:title","label":"Title","values":["Thermogravimetric, thermopower, and electrical conductivity studies of the Ba₂YCu₃O₇₋ₓ system"]}]}],"canonical_facts":{"dc:creator":["Brannon, C. John"],"dc:date.available":["2016-02-10T08:00:00Z"],"dc:description.abstract":["\"The Ba2YCu3O7-x system was investigated using thermogravimetric, thermopower, and d.c. electrical conductivity techniques. The system was found to exhibit a semiconductor to metallic transition coincident with the documented orthorhombic to tetragonal phase transition. Conduction is accomplished in the semiconducting phase by an activated small hopping polaron mechanism. The oxide was observed to be a p-type semiconductor over the temperature and oxygen activity ranges studied.
The conductivity, carrier concentration, and mobility behaviors of the oxide are primarily functions of its oxygen content. All three properties exhibited only a slight temperature dependence. The carrier concentration is essentially constant at a given oxygen content. The carrier concentration ranged from about 0.5 x 1021/cm3 at 800°C and O = 6.3 to 6 x 1021/cm3 at 500°C and O = 6.95. Mobilities ranged from about 0.05 cm2/V sec. at 600°C and O = 6.4 to 0.5 at 800°C and O = 6.7\"--Abstract, page ii.
"],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/714"],"dc:subject":["Ceramic Materials"],"dc:title":["Thermogravimetric, thermopower, and electrical conductivity studies of the Ba₂YCu₃O₇₋ₓ system"],"dc:type":["Dissertation - Restricted Access"],"thesis:degree_name":["Ph. D. in Ceramic Engineering"],"thesis:institution_name":["University of Missouri--Rolla"]},"updated_at":"2026-07-24T03:18:50Z"}