Improvement of Trapped Field Performance by Combining a Holed REBCO Bulk With a Cross-Shaped Soft-Iron Yoke

For efficient pulsed-field magnetization (PFM) of REBCO bulk magnets, we have proposed a method of preferentially allowing the magnetic flux to penetrate through small holes at the outer periphery of the bulk material by intentionally reducing its superconducting properties. Furthermore, we paid attention to the soft-iron yoke used to expose the magnetic flux to the bulk material for a long time during PFM and confirmed that the cross-shaped yoke improves magnetizing efficiency. In this paper, we propose a method of applying a pulsed magnetic field using a cross-shaped yoke to a bulk with four holes on its periphery, and we evaluate the magnetization characteristics by experiments and numerical analysis for a case where the yoke is placed in an area with small holes and an area without them. Those results showed that the yoke placed in the area without holes had superior magnetizing characteristics.