AC losses in high-temperature superconducting (HTS) tapes are critical in applications such as magnets for nuclear fusion, high energy particle accelerators [1] rotating electric machines, transformers and superconducting magnetic energy storage [2]. However, the presence of alternating magnetic fields can induce AC losses in superconducting tapes, leading to reduced efficiency and performance. It has been shown that the losses can be significantly reduced by tape striation[3]. We enhanced the latter method by introducing a novel approach, involving electrically insulating thin layers with high thermal conductivity onto superconducting tapes. The insulating layers serve two purposes: (1) to protect the superconductor in created grooves, and (2) to enhance the thermal stabilization of the superconducting tape without introducing excessive coupling losses[4]. Firstly we compare the AC losses of HTS tapes striated by three different methods: chemo-mechanical, photolitography, and laser ablation. Subsequently, the superconducting tapes exhibiting the most promising results from these methods were deposited with a thin layer possesing both good thermal conductivity and relatively high electrical resistance. We then compared the performance of such modified tapes with reference tapes (without the deposited layer). Based on the measurements of the deposited tapes properties such as the AC loss, transport properties and thorough structural analysis, we proposed the most optimal combination of striation and deposition technique yielding minimal AC losses in HTS tapes.
[1] Z. Guo et al., “AC loss and contact resistance in highly flexible rebco cable for fusion applications”, Superconductivity, roč. 2, s. 100013, jún. 2022, doi: 10.1016/j.supcon.2022.100013.
[2] G. Messina, L. Morici, G. Celentano, M. Marchetti, a A. Della Corte, “REBCO Coils System for Axial Flux Electrical Machines Application: Manufacturing and Testing”, IEEE Transactions on Applied Superconductivity, roč. 26, č. 3, s. 1–4, apr. 2016, doi: 10.1109/TASC.2016.2552158.
[3] A. Godfrin et al., “Influence of the Striation Process and the Thickness of the Cu-Stabilization on the AC Magnetization Loss of Striated REBCO Tape”, IEEE Transactions on Applied Superconductivity, roč. 27, č. 6, s. 1–9, sep. 2017, doi: 10.1109/TASC.2017.2716820.
[4] M. Búran et al., “Impact of a REBCO coated conductor stabilization layer on the fault current limiting functionality”, Supercond. Sci. Technol., roč. 32, č. 9, s. 095008, júl. 2019, doi: 10.1088/1361-6668/ab2c8e.
This work was supported by: (1) the Slovak Research and Development Agency, project No. APVV-20-0056, (2) the Grant Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences, project No. 1/0205/21 and (3) European Regional Development Fund, project No. ITMS2014+: 313011BUH7