Grain Boundary Doping May Improve High-Temperature Superconducting Wire

Abstract

Superconducting wire is a central part of many of the applications devised for high-temperature superconductors in the 15 years following their discovery. With transition temperatures Tc above the boiling temperature of liquid nitrogen (77 K), these superconductors have the potential to provide cheap, low-loss wires capable of carrying large currents. The technological realization of this potential has been difficult, however, due in part to the anisotropic character of the ceramic high-Tc materials. Although single crystals of high-Tc superconductors have high critical current densities—the figure of merit in wire applications—polycrystalline wires suffer from significantly reduced current-carrying ability.