Investigations of YBaCuO Materials with Near-Room-Temperature Resistivity Transitions
Abstract
This annual technical report describes the continual superconductivity research on the materials and structural phases responsible for the above 200-K superconducting transitions, their synthesis conditions, and the study of the physical properties associated with these transitions. Superconducting resistive transition and magnetic flux trapping phenomena have been observed in mixed-phase ceramic samples of YBaCuO (e.g. Y5Ba6Cu11Ox) and on the surfaces of YBa2Cu3O7 single crystals in the temperature range 230 K to 270 K. Near room-temperature oxidation studies show that the properties can change, including a large resistance decrease over a 3-month period. This behavior is consistent with the formation of a different oxide phase on the surface of the grains. Structural analyses by x-ray diffraction and high-resolution transmission electron microscopy indicate these samples have surfaces with large amounts of defect structures as well. Correspondingly these surface phases/ structures may be responsible for the above 200-K transitions.... Superconductivity, Room-temperature superconductivity, YBaCuO Superconductors
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 14, 1993
- Accession Number
- ADA268016
Entities
People
- J. T. Chen
- Lowell E. Wenger
Organizations
- Wayne State University