Lift Factor Analysis of Multifilamentary Coated Conductor Produced Using Two Level Undercut-Profile Substrates

Here we present a detailed characterization of the critical current density of YBa₂Cu₃O_7-œ (YBCO) two level undercut-profile substrate (2LUPS)-based samples made at the Technical University of Denmark (DTU) using Hastelloy substrate. The CC architecture was produced at Bruker HTS by means of alternating beam assisted deposition (ABAD) and pulsed laser deposition (PLD). The magnetization of different samples having all the same size, but with various numbers of filaments, including a non-filamentary reference sample have been measured in applied magnetic fields up to 16T and at temperatures ranging from T=2K to 77K. A simple multiple rooftop model is proposed to estimate the critical current density of the filaments and it has been observed that filaments of 250μm and 500μm width are providing similar critical current densities in the order of J_c ≈ 2.3 MA/cm² at T=4.2K and B=10T as well as the reference samples without filaments. This result indicates that the filaments have been fabricated with no degradation of the superconductor and that the filaments are decoupled with non-superconducting material. Finally, the lift factor of the critical current I_c with respect to T=77K and self field of the 2LUPS samples is estimated. This is reaching 10 at T=4.2 K and B=10 T.