High performance superconducting wire in high applied magnetic fields via nanoscale defect engineering

High temperature superconducting (HTS) wires capable of carrying large critical currents with low dissipation levels in high applied magnetic fields are needed for a wide range of applications. In particular, for electric power applications involving rotating machinery, such as large-scale motors and generators, a high critical current, I_c, and a high engineering critical current density, J_E, in applied magnetic fields in the range of 3-5 Tesla (T) at 65K are required. In addition, exceeding the minimum performance requirements needed for these applications results in a lower fabrication cost, which is regarded as crucial to realize or enable many large-scale bulk applications of HTS materials. Here we report the fabrication of short segments of a potential superconducting wire comprised of a 4νm thick YBa₂Cu₃O_7-δ (YBCO) layer on a biaxially textured substrate with a 50% higher I_c and J_E than the highest values reported previously. The YBCO film contained columns of self-assembled nanodots of BaZrO₃ (BZO) roughly oriented along the c-axis of YBCO. Although the YBCO film was grown at a high deposition rate, three-dimensional self-assembly of the insulating BZO nanodots still occurred. For all magnetic field orientations, minimum I_c and J_E at 65K, 3T for the wire were 353Acm^-1 and 65.4kAcm^-2, respectively.