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TT: Fachverband Tiefe Temperaturen
TT 45: Focused Session: 100 Years of Superconductivity
TT 45.3: Invited Talk
Thursday, March 17, 2011, 11:40–12:10, HSZ 03
Large Scale Applications of Superconductors and the Challenges that they have posed — •David Larbalestier — National High Magnetic Field Laboratory, Florida State University
Already in 1913 Onnes envisioned using superconductors to create 100 kGauss fields well beyond any possibility provided by cooling Ag or Cu with liquid helium. Only some "bad places" in his Hg and Pb wires seemed to impede his first attempts at this dream, one that he imagined a short ongoing effort would quickly resolve. In fact, resolution required 50 years, understanding the subtle effects of alloy and compound superconductivity, closure of the theory-experiment gap and inspired experiments with Nb3Sn. Suddenly in 1961, it all came together and Onnes’s dreams of 100 kGauss magnets were soon comfortably surpassed. In the last 45 years virtually all superconducting magnets have been made from just two Nb-base materials, Nb-Ti and Nb3Sn, operating in liquid He. In 1987 cuprates with Tc > 100K suggested that superconducting applications could leave liquid helium behind, and extend well beyond the science to the electrical engineering market. However, making conductors from complex cuprates posed many more challenges than envisaged in 1987 (echoes of Onnes in 1913?). Now that these challenges have largely been met in REBa2Cu3O7 coated conductors, it is time to talk too about practical requirements for new superconductors. At 100, one can still be sure that the "right" new superconductor will find broad application and the ubiquity of superconductivity in materials phase space suggests that many new applications lie ahead in the 2nd superconducting century.