Characteristics of an HTS Magnet Wound With 12-mm Zr-Doped HTS Tape

This paper examined the properties of an high-temperature superconducting (HTS) magnet, such as the Ic-B relation and critical current, with pancake windings of a 12-mm-wide Zr-doped HTS tape. Considering the width of the Zr-doped HTS tape was 12 mm, which was three times wider than that of a conventional 4 mm tape, the current distribution at the cross-section of the 12-mm tape was assumed to be non-uniform. The HTS magnet consisting of four pancake windings of the 12-mm tape was chosen as the model for calculations and measurements. The inner diameter and the number of turns of the pancake winding were 30 mm and 88 turns, respectively. When the critical current of the HTS magnet was calculated assuming the same critical current for all pancake windings, the critical current of the whole magnet was limited by the middle pancake windings. The limiting of the magnet current by the middle pancake windings was due to properties of the Zr-doped HTS tape. After allocating the pancake windings with higher critical current to the middle part of the HTS magnet, the critical current was limited by the top and bottom pancake windings.