Superconducting materials for large scale applications

• Published in: Proceedings of the IEEE Vol. 92; no. 10; pp. 1639 - 1654
• Main Authors: Scanlan, R.M., Malozemoff, A.P., Larbalestier, D.C.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-10-2004; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: APPLICATIONS; COMPOSITES; Conducting materials; Conductors; COPPER OXIDE; Cuprates; ELECTRICAL CONDUCTIVITY; Large-scale systems; Magnetic anisotropy; Magnetic devices; Magnetic materials; Markets; Materials selection; NMR; Nuclear magnetic resonance; Perpendicular magnetic anisotropy; Power transmission; Superconducting magnets; Superconducting materials; SUPERCONDUCTIVITY; SUPERCONDUCTORS; YBCO superconductors; YTTRIUM OXIDE
• ISSN: 0018-9219; 1558-2256
• DOI: 10.1109/JPROC.2004.833673

Since the 1960s, Nb-Ti (superconducting transition temperature T/sub c/=9 K) and Nb/sub 3/Sn (T/sub c/=18 K) have been the materials of choice for virtually all superconducting magnets. However, the prospects for the future changed dramatically in 1987 with the discovery of layered cuprate superconductors with T/sub c/ values that now extend up to about 135 K. Fabrication of useful conductors out of the cuprates has been difficult, but a first generation of silver-sheathed composite conductors based on (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ (T/sub c//spl sim/110 K) has already been commercialized. Recent progress on a second generation of biaxially aligned coated conductors using the less anisotropic YBa/sub 2/Cu/sub 3/O/sub 7/ structure has been rapid, suggesting that it too might enter service in the near future. The discovery of superconductivity in MgB/sub 2/ below 39 K in 2001 has brought yet another candidate material to the large-scale applications mix. Two distinct markets for superconductor wires exist-the more classical low-temperature magnet applications such as particle accelerators, nuclear magnetic resonance and magnetic resonance imaging magnets, and plasma-containment magnets for fusion power, and the newer and potentially much larger market for electric power equipment, such as motors, generators, synchronous condensers, power transmission cables, transformers, and fault-current limiters for the electric utility grid. We review key properties and recent progress in these materials and assess their prospects for further development and application.