(1) New world record IcL value of 112,166Am set with yttrium-based oxide superconducting wire
The distinguishing feature of yttrium-based superconducting wire is that it has a high critical current density, and critical current in the presence of a magnetic field is large at the temperature of liquid nitrogen. Thus this wire has the potential for application not only in cable, but also in superconducting power storage equipment, motors, generators, transformers and other equipment. When making yttrium-based superconducting material into wire, there is a need to regularly align crystals in the wire. It has been difficult to achieve extended lengths of wire, but we were successful this time. The fabricated wire set new records for length (L) of 368m, and critical current (Ic) of 304.8A. The IcL value, which is a product of this length and critical current, set a new world record of 112,166Am. Wire was fabricated using the IBAD/PLD method which combines two processes: a buffer layer fabrication process employing the IBAD method, and a superconducting layer fabrication process employing the laser deposition method (PLD method).

(2) Development of high-speed buffer layer fabrication method more than 5 times faster than previous method
In realizing high-performance yttrium-based superconducting wire, it is necessary for crystals to be regularly aligned in the longitudinal direction of the wire. Therefore Fujikura has developed the IBAD method for controlling crystallinity of the buffer layer which is below the superconducting layer. Reducing the cost of the buffer layer with the IBAD method will contribute greatly to reducing wire costs in the future, and thus we have worked to develop a high speed layer formation method. By using a new buffer layer structure, we recently achieved a dramatic increase in speed of over 5 times compared to the previous layer formation speed of 3-5m/h.
This new buffer layer combines magnesium oxide and gadolinium/zirconium oxide and has a total thickness of 0.3µm. It has the same performance as conventional types. A superconducting layer was formed on top of this new buffer layer, and it was confirmed that a critical current of 200A or more could be obtained. These results show that this technology can greatly reduce the \12/Am current cost target of this project.
In the future, we will make efforts to further lengthen wire and improve performance by using this new buffer layer.