Current Transport Properties of TFA-MOD Processed Long-Length Y_xGd₁-_xBa₂Cu₃O_y Coated Conductor Doped with BaZrO₃ Artificial Pinning Centers

We have investigated the current transport properties of batch furnace processed TFA-MOD Y_xGd₁-_xBa₂Cu₃O_y (YGdBCO) coated conductor (CC) doped with nanoscale BaZrO3 artificial pinning centers (APCs). As the comparison with those of previous processed YGdBCO CC, it has been confirmed that the present process is very effective to improve current carrying performance of the CC at not only high-temperature but also low-temperature region, for example, the I_c at 4.2 K and 17 T is 450 A/cm-w, i.e., the engineering J_c is 4.3 × 10⁸A/m², which is comparable value to that of Nb³Sn wire at 4.2 K. In addition, angular dependences of the I_c clearly show the effectiveness of the APCs. Namely, the minimum I_c in the whole angle region at 77 K, 3 T increase from 7 to 35 A/cm-w, and the anisotropy of I_c is reduced. We will also discuss the analytical expression of in-field current transport property based on the percolation transition model and the scaling law of the flux pinning. By using this analysis, electric field versus current density characteristics in arbitrary conditions of temperature and magnetic field can be described, and also, the statistical distribution of J_c can be estimated. These results are important not only for the design of superconducting devices using CCs but also for understanding the pinning properties.