Pulsed field magnetization of large-grain Gd-Ba-Cu-O bulk superconductor

We measured the field distribution and the variation of temperature in a large-grain Gd-Ba-Cu-O bulk superconductor during pulse field magnetization. When the applied field was below 3.1 T, the temperature rise due to flux motion was small because the magnetic flux penetrated only the surface thin layer. The trapped field increased with increasing field, although the sample temperature was raised and the trapped field reached 1.6 T for the applied pulse field of 3.1 T. However, when the applied field exceeded 3.1 T, the trapped field suddenly decreased due to an excessive temperature rise in the sample. Thus there is an optimum peak field for the pulse field magnetization process. (C) 2003 Elsevier B.V. All rights reserved.