Magnetizing characteristic evaluation of REBCO bulk in PFM using different yokes

A REBCO bulk magnet is able to generate a several-Tesla-class magnetic field by a compact system with low power consumption. Pulsed field magnetization (PFM), which is one of major magnetization method, has the advantage that the bulk is activated using a conventional equipment in a few seconds, and, therefore, it is suitable for practical use. However, a trapped field is lower than the maximum performance of material. To increase the field, improvement of magnetization method and modification of exciting equipment are considered. We aim to improve the trapped field by changing the exciting system simply and inexpensively. In the bulk magnet system, soft-iron yokes are generally used to extend the pulse width. This paper evaluated magnetizing characteristic quantitatively. A single pulsed field was applied to a new GdBCO bulk using φ64-mm and φ80-mm soft-iron yokes. The pulse width of φ80-mm yoke was about 35% longer than that of φ64-mm yoke. When comparing the trapped flux density and total magnetic flux, these values of φ80-mm yoke were higher than those of φ64-mm yoke. Also, the temperature rise of φ80-mm yoke was decreased by approximately 5% as compared with φ64-mm yoke, implying that the same effect as the long-pulse method was achieved.