Fabricating polycrystalline high-Tc superconductors

Many applications of high-temperature superconductors require the ability to carry large currents in high magnetic fields. Electrical properties of single crystals and thin films offer hope that suitable electrical properties will be obtained in polycrystalline materials. Novel microstructures can be produced by melt-recrystallization processes that can be characterized by oriented crystallites. The large critical current densities required for many applications have been demonstrated by powder-in-tube and melt-texturing processes to form bulk polycrystalline materials. Plastic forming techniques, such as extrusion and tape casting, offer the advantage of fabricating long and continuous coils. Near-term products that operate in low magnetic fields include current leads, shielding devices and high-quality resonant cavities