Trapped Field Distribution within a Cylindrical Hole in Sm-Ba-Cu-O Bulk Superconductor

To study the possibility of HTS applications in the design of magnets for particle accelerators, we investigated the trapped field distribution in a bulk superconductor. An array of Hall probes, calibrated at liquid nitrogen temperature, was used to monitor the trapped field distribution in a hole (10 mm in diameter) in a rectangular bulk superconductor (15 mm thickness) as a function of time. The bulk superconductor was placed in an external field created by a dipole magnet, where the field strength was varied up to about 1.5 T. The decay process of the trapped field was monitored using the Hall probe array. The decay speed was observed to be dependent on the initial external field applied, the distance from the edge of the material and the trapped field strength. The results are summarized in this report