Pulsed Field Magnetization of Large MgB2Bulk Fabricated by Reactive Liquid Mg Infiltration

Abstract

Pulsed field magnetization (PFM) was performed for the first time on a large MgB2 bulk 50 mm diameter fabricated by a reactive liquid Mg infiltration (Mg-RLI) method, and the time dependence of the local field BLC(t) and the trapped field profiles were measured. The trapped field of Bz=0.47 T and the total trapped flux of Φ=0.50 mWb were achieved at Ts=23 K and both values decreased with increasing temperature Ts. The experimental results can be qualitatively reproduced by numerical simulation using electromagnetic and thermal fields for PFM. The flux dynamics and the heat generation/propagation in the MgB2 bulk during PFM were in clear contrast with those in REBaCuO superconducting bulks because of the large thermal conductivity, small specific heat, and narrow temperature margin against the transition temperature Tc.