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Increasing Critical Current of High Temperature Superconductors

IP.com Disclosure Number: IPCOM000035251D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Laibowitz, RB: AUTHOR [+3]

Abstract

For most applications, the new class of oxide high temperature superconductors (such as LaSrCuO, YBaCuO and Tl and Bi based oxides) should have high critical currents, preferably in the range at or above 1,000,000 Ao/cm2. Several techniques are described for achieving this.

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Increasing Critical Current of High Temperature Superconductors

For most applications, the new class of oxide high temperature superconductors (such as LaSrCuO, YBaCuO and Tl and Bi based oxides) should have high critical currents, preferably in the range at or above 1,000,000 Ao/cm2. Several techniques are described for achieving this.

The first step to improve critical currents is to avoid weak link coupling between grains in oxide superconductors either by eliminating grains altogether in single crystals or single crystal films, or else by having more intimate coupling between grains to reduce the electrical barriers at the grain boundaries. The latter could be achieved, for example, by preferential grain orientation, and by hot pressing to densify the material.

The achievement of homogeneous material is not sufficient to achieve high critical current, because in strongly Type II material, pinning centers must be present to pin flux lines, whose motion is responsible for the onset of resistive loss. Two steps are required to achieve high critical current: 1) more homogeneous material (on the scale of grain boundaries), and at the same time
2) the introduction of strong pinning centers within the homogeneous material.

The optimal pinning centers have dimensions comparable to the size of the flux lines, namely, to the size of the penetration depth, which is in the range of a few thousand Angstroms in these materials. One method which directly creates such pinning centers in a distribution exactly matching the flux line (vortex) lattice is to first...