Magnetic Flux-Trapping of Anisotropic-Grown Y-Ba-Cu-O Bulk Superconductors during and after Pulsed-Field Magnetizing Processes

11th European Conference on Applied Superconductivity

Oka, T.^1 ; Yamada, Y.^1 ; Horiuchi, T.^1 ; Ogawa, J.^1 ; Fukui, S.^1 ; Sato, T.^1 ; Yokoyama, K.^2 ; Langer, M.^3

Niigata University, 8050 Ikarashi-2-nocho, Nishi-ward, Niigata

950-2181, Japan^1

Ashikaga Institute of Technology, 268-1 Ohmae-cho, Ashikaga, Tochigi

326-8558, Japan^2

IFW Dresden, Helmholzstr. 20, Dresden

01069, Germany^3

关键词: Anisotropic grain growth;    Bulk superconductors;    Different distributions;    Flux penetration;    High temperature superconducting bulks;    Magnetic flux penetration;    Magnetizing process;    Pulsed-field magnetization;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012039/pdf
DOI  :  10.1088/1742-6596/507/1/012039

来源: IOP

【 摘 要 】

The magnetic flux penetration into the melt-textured Y-Ba-Cu-O high temperature superconducting bulk magnets were precisely evaluated during and after the pulsed field magnetization processes operated at 30 K. The bulk magnets were carefully fabricated by the cold seeding method with use of a single and a pair of seed crystals composed of the Nd-Ba-Cu-O thin films. These seed crystals were put on the top surfaces of the precursors to let the large grains grow during the heat treatments. We observed the flux penetrations which occurred in the lower applied-field regions at around 3.1 T for the samples bearing the twin seeds than those of the single-seeded crystals at around 3.8 T. This means that the magnetic fluxes are capable of invading into the twin-seeded samples more easily than the single-seeds. It suggests that the anisotropic grain growths of parallel and normal to the rows of seed crystals affects the variations of Jcvalues with different distributions of the pinning centers, results in the preferential paths for the invading magnetic fluxes.