AC loss properties of laser-scribed multi-filamentary GdBCO coated conductors with artificial pinning centres

RE₁Ba₂Cu₃O₇-∂ (RE: Rare Earth, Gd, Y and so on) coated conductors have a large aspect ratio and also anisotropy in critical current density. For practical application of REBCO tapes, we evaluated J_C and ac loss properties in a wide range of temperature and magnetic field. The induced ac losses due to the perpendicular magnetic field to a tape face are considerably huge. Therefore, in case that REBCO coated conductors are applied electric power machines and devices, ac loss induced in the windings should amount to a great part of the total heat load. We proposed an ac loss reduction method, which is combined with a laser scribing technique and a special winding process into a multifilamentary structure. Additionally, we are trying to enhance critical current density J_C, by doping artificial pinning centre. In this study we investigated the ac loss properties of multi-filament structural GdBCO tapes with BZO nanolods as artificial pinning centers. We measured ac losses of 5, 10, 20-filament GdBCO tapes by using a saddle-shaped pickup coil. Consequently we confirmed the ac loss decreased in inverse proportion to the number of filaments even in the GdBCO tapes with enhanced J_C by introducing artificial pinning centers.