High Temperature Superconductors With Improved Current Densities

Period of Performance: 04/10/1991 - 04/10/1993

$405K

Phase 2 SBIR

Recipient Firm

Cryo-power Assoc.
PO Box 478
Los Alamos, NM 87544
Principal Investigator

Abstract

Bulk ceramic high temperature superconductors have all the required properties to revolutionize electrotechnology, except one. They have high Tc and HcE2, but lack usable Jc's. At least 10,000 A/cmE2 is needed for most power engineering applications. Low current densities are caused by three interacting factors: anisotropy in the crystal structure, imperfections at the grain boundaries, and weakness of the bond between the copper and oxygen atoms, particularly in Y-123. When that bond is broken during severe processing, non-superconducting impurity phases are formed, which then act as weak links. Our approach to improving Jc is three-pronged: select a superconductor that is less likely to decompose, maintain control over its purity, and neutralize the grain boundaries by texturing or plastic deformation. As part of a Phase I SBIR effort, CryoPower has produced the more stable Y-124 compound in commercial quantities. The main thrust of the Phase 2 effort will be to texture and plastically deform Y-124. The possible pay-off in making bulk high temperature superconductors practical ranges from improved traveling wave tubes, to electromagnetic bearings, motors, generators, EMP shields and levitated trains.