Magnetization Characteristics of YBa2Cu3O7−δ Bulk Superconductors Prepared From Modified Precursor Powder.

The microstructure of a bulk superconductor may fundamentally affect its field trapping and levitation performance for practical applications. Recently, a modified top-seeded melt growth using only Y2O3 and Ba2Cu3Ox precursor powder combined with a layered arrangement of graded Y2O3 content was reported to significantly refine Y2BaCuO5 particles as well as their distribution. In this paper, we have evaluated and compared the trapped field of a CPP (conventional precursor powder), an MPP (modified precursor powder), and an L-MPP (layered and compositionally graded) sample magnetized by both field cooling magnetization (FCM) and pulsed field magnetization (PFM) at 77 K. The 25 mm diameter YBa2Cu3O7-δ sample made from L-MPP shows the highest trapped field of remarkably 1.01 T and an advanced in-field performance. And the trapped fields achieved via PFM are close to (>93%) that obtained by FCM for all the three samples. However, a more dramatic flux motion has been observed for the MPP and L-MPP sample during the PFM process. The resulted trapped field distribution exhibited the effect of the homogeneity of the sample on the trapped field. [ABSTRACT FROM AUTHOR]