Pulsed field magnetization properties for Gd-Ba-Cu-O superconductors impregnated with Bi-Sn-Cd alloy

We present a post-fabrication treatment that improves thermal conductivity of bulk Gd-Ba-Cu-O magnets for pulsed field magnetization (PFM). A small hole about 1 mm in diameter was artificially drilled into the center of bulk Gd-Ba-Cu-O 25 mm in diameter and 18 mm in thickness. An aluminum wire was inserted into the hole, and then the sample was subjected to the impregnation by using Bi-Sn-Cd alloy. We employed PFM to magnetize Gd-Ba-Cu-O bulk superconductors with and without the alloy impregnation treatment. The temperatures of the samples were monitored with thermocouples, and local magnetic field density was measured with a Hall sensor. It was found that the alloy impregnation was effective in suppressing the temperature rise by 4 K and in increasing the trapped field by 25% at 44 K. The present results show that the alloy impregnation treatment enhanced the thermal conductivity of bulk Gd-Ba-Cu-O, and thereby improved the field trapping ability.