Possible solution of the grain-boundary problem for applications of high-Tc superconductors

It is shown that the critical current density of high-Tc wires can be greatly enhanced by using a three-fold approach, which consists of grain alignment, doping, and optimization of the grain architecture. According to model calculations, current densities of 4×106 A/cm2 can be achieved for an average grain alignment of 10° at 77 K. Based on this approach, a road to competitive high-Tc cables is proposed.