Accession Number : ADA293405

Title :   Investigations of YBaCuO Materials with Near-Room-Temperature Resistivity Transitions.

Descriptive Note : Final rept. 15 Jun 91-14 Oct 94,

Corporate Author : WAYNE STATE UNIV DETROIT MI DEPT OF PHYSICS

Personal Author(s) : Wenger, Lowell E. ; Chen, J. T.

PDF Url : ADA293405

Report Date : 14 DEC 1994

Pagination or Media Count : 506

Abstract : This final 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. Resistive transitions having superconducting-like character have been observed in multi-phase ceramic YBaCu0 samples and on surfaces of nominal YBa2Cu3O7 single crystals in the temperature range of 260 K to 340 K. The appearance of these transitions appears to require certain experimental measuring conditions including an oxygen atmosphere during measurments. Magnetization studies on these materials show a flux-trapping hysteretic behavior at similar temperatures, i.e., a more diamagnetic behavior in the zero-field-cooled- magnetization than the field-cooled-magnetization characteristic of a weak superconducting phase being present. The synthesis conditions and structural information on multi-phase YBaCu0 samples exhibiting reproducible flux-trapping phenomenon at 336 K is also detailed. In addition, studies of the paramagnetic Meissner effect on a niobium disk and of Josephson properties in YBa2Cu3O7 single crystals and YBaCu0 thin films are reported. jg

Descriptors :   *THIN FILMS, *SINGLE CRYSTALS, *BARIUM, *COPPER OXIDES, *SUPERCONDUCTIVITY, *YTTRIUM, MEASUREMENT, SYNTHESIS, PHYSICAL PROPERTIES, STRUCTURAL PROPERTIES, COMPOSITE MATERIALS, PHASE, ROOM TEMPERATURE, OXYGEN, NIOBIUM, DISKS, RANGE(EXTREMES), MAGNETIZATION, LOW STRENGTH, ATMOSPHERES, PARAMAGNETISM, DIAMAGNETISM.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Laminates and Composite Materials
      Crystallography
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE