HTS materials-requirements for magnets

The potential of bulk high temperature superconductors to generate large d.c. magnetic fields, associated with their ability to carry current without resistance, is particularly attractive for both permanent magnet and wire-wound applications. All magnetic fields are produced by the motion of charges. The field generated by conventional iron-based permanent magnets, however, is limited by the number of Bohr magnetons per atom whereas that produced by copper wire solenoids is determined by the current carrying capacity of the windings-neither are able to generate magnetic fields in air of much more than 1 T at 77 K. As a result, real engineering gains could be achieved in many magnetic field based applications by replacing conventional materials with HTS.