Trapped Field Enhancement of a Thin, High-Jc MgB2 Bulk without Flux Jumps using Pulsed Field Magnetization with a Split-type Coil with a Soft Iron Yoke

摘要

We have investigated the suppression of flux jumpsand the enhancement of trapped field on a thin, high-J$_{c}$ MgB₂bulk (30 mm in diameter and 7 mm in thickness) for the pulsedfield magnetization (PFM) using a split-type coil with a soft ironyoke, and compared the results to those magnetized using thesplit-type coil without a yoke and a solenoid-type coil with a yoke.A maximum-trapped field, B$_{z}$, of 0.71 T at 14 K was achieved onthe bulk surface without flux jumps by using the split coil withyoke. On the other hand, low B$_{z}$ values with flux jumps wereobserved for the cases using the split-type coil without a soft ironyoke, and the solenoid-type coil with a yoke. These resultsreproduce previous ones for a thick, high-J$_{c}$ MgB₂ bulk (22 mmin diameter and 15 mm in thickness), for which the trapped fieldwas enhanced to a record high value of B$_{z}$=1.10 T at 13 K byPFM using the split-type coil with a yoke.