Bulk superconductors can act as trapped-field magnets with the potential to be used for many applications such as portable medical magnet systems and rotating machines. Maximising the trapped field, particularly for practical magnetisation techniques such as pulsed field magnetisation (PFM), still remains a challenge. PFM is a dynamic process in which the magnetic field is driven into a superconducting bulk over milliseconds. This flux motion causes heating and a complex interplay between the magnetic and thermal properties. In this work, the local flux density during PFM in a MgB₂ bulk superconductor has been studied. We find that improving the cooling architecture increases the flux trapping capabilities and alters the flux motion during PFM. These improvements lead to the largest trapped field (0.95 T) for a single MgB₂ bulk sample magnetised by a solenoidal pulsed field magnet. The findings illustrate the fundamental role bulk cooling plays during PFM.

块状超导体可以充当场强磁铁，有可能用于许多应用，例如便携式医疗磁铁系统和旋转机器。最大化俘获场，特别是对于脉冲场磁化 (PFM) 等实用磁化技术，仍然是一个挑战。PFM 是一个动态过程，其中磁场在几毫秒内被驱动到超导体中。这种通量运动会导致发热以及磁性和热属性之间复杂的相互作用。在这项工作中，在 MgB ₂中 PFM 期间的局部磁通密度体超导体进行了研究。我们发现改进冷却架构会增加通量捕获能力并改变 PFM 期间的通量运动。对于由螺线管脉冲磁场磁体磁化的单个 MgB ₂大块样品，这些改进导致最大的俘获场 (0.95 T) 。研究结果说明了大容量冷却在 PFM 过程中的基本作用。