A significant program in high-T_c (critical transition temperature) superconductivity is being conducted in MSEL and other Laboratories at NIST. The primary focus of the MSEL Program is on bulk superconducting materials for wire and magnet applications. In carrying out this program, researchers in MSEL work closely with their counterparts in other NIST Laboratories, and collaborators in U.S. industry and other National Laboratories.

The primary thrusts of the program are as follows:

• Phase equilibria - Work is being performed in close collaboration with the U.S. Department of Energy (DOE) and its national laboratories to provide the phase diagrams necessary for processing these unique ceramic materials. A prime objective is the development of the portions of the phase diagram for the Pb-Bi-Sr-Ca-Cu-O system relevant to production of the high T_c materials.

• Flux pinning - This project makes use of a unique magneto-optical imaging facility to examine flux pinning in a variety of materials. Much of this work is being conducted in collaboration with American Superconductor Corporation. In addition techniques for better interpretation of magnetic measurements are being developed.

• Damage mechanisms - Work is being carried out under a joint CRADA (cooperative research and development agreement) with American Superconductor Corporation as part of the "Wire Development Group" which involves a number of DOE National Laboratories and the University of Wisconsin to elucidate the effects of strain on the loss of current in superconducting wires. The primary tool being employed is the use of microfocus radiography available at the NIST beamline at the Brookhaven National Laboratory.

• Database - A high-T_c superconductor database has been developed in collaboration with the National Research Institute for Metals (NRIM) in Japan. The High- Temperature Superconductor Database (HTSD) includes evaluated open-literature data on numerous physical, mechanical, and electrical properties of a variety of chemical systems. The first version of the database is now for sale by the Office of Standard Reference Data.

• Crystal structure - Thermal neutron diffraction techniques and profile refinement analyses are being utilized to investigate crystal and magnetic structures, composition, and crystal chemical properties. This research is being carried out in collaboration with a number of industrial and university experts.

Projects

Magnetic Measurements of Superconductors

For further information about the High-T_c Superconductivity Program, please contact S. W. Freiman at 301-975-6119 or e-mail requests to [email protected].

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Last modified: Mon Jan 06 09:46:15 1997 Metallurgy Webmeister