Current-carrying properties of REBCO multi-filamentary tapes prepared by reel-to-reel ultraviolet picosecond laser cutting

Abstract REBCO high-temperature superconductors have been widely used in high magnetic field applications, because of their excellent critical current properties and high critical temperature. However, REBCO tape has an extremely large width-to-thickness ratio (typically in the range of 1000–10 000) which causes power dissipation to be too high in applications. One of the most effective ways to reduce AC loss is to divide the superconducting layer in the REBCO tape into filaments. The current-carrying properties degradation behavior of the prepared multi-filamentary tape is the focus of attention. In this study, REBCO multi-filamentary tapes are tested with different numbers of filaments (2-filament, 6-filament, and 10-filament) by cutting the copper-stabilizing layers and superconducting layers through a self-developed reel-to-reel ultraviolet picosecond laser cutting device. The findings indicate that the cut groove has a depth of approximately 30 μ m and the width of the groove in the superconducting layer measures around 15 μ m. Meanwhile, the research found that ultraviolet picosecond laser cutting does not cause substantial degradation in the I C . Under self-field conditions at 77 K, the I C decreases with the number of filaments, and the degradation of I C is less than 13% in a 10-filament tape, the corresponding decrease of J C is only about 10%. Similarly, at 4.2 K and under various high-field (10 T, 12 T, 14 T) conditions, the I C variation trends of REBCO high-temperature superconducting (HTS) multi-filamentary tapes and non-striated tapes are fundamentally similar, both decreasing as the applied vertical magnetic field increases. Furthermore, it was found that a constant tension of 50 MPa, 100 MPa, and 200 MPa had no effect on the current-carrying properties of the REBCO HTS multi-filamentary tapes.