Magnetic properties of Ag-added Gd–Ba–Cu–O superconductors
摘要
In order to obtain helpful guidelines for designing high-Tc bulk superconductor magnet systems, the gap, temperature and time dependence of the trapped field for Y–Ba–Cu–O and Gd–Ba–Cu–O/Ag bulk superconductors were measured. For the gap dependence, we compared the experimental results and the analytical solution on the condition that Jc is constant for the disk-shaped bulk superconductor, and we found that the analytical solution corresponds well with the experimental results. The peak value of the trapped field reached 4.6 T at 63 K for the Gd–Ba–Cu–O bulk superconductor, and the flux creep rate at 63 K was slower than that at 70 and 77 K. This indicates that cooling down to at least 63 K creates superior conditions for the bulk magnet in respect of the increasing trapped field and its stability.