Flux Dynamics and Thermal Behavior of a GdBaCuO Bulk Magnetized by Single- and Double-Pulse Techniques Using a Split-Type Coil

We have investigated the trapped field properties of a GdBaCuO disk bulk during single- and double-pulsed field magnetization (PFM) using a split-type coil for various pulse sequences for the first time. It is well known that the multi-PFM technique using a solenoid-type coil and the single-PFM technique using a split-type coil are effective to enhance the trapped field due to a lower temperature rise. However, it was found, in this work, that the trapped field by double-PFM using the split-type coil was not enhanced in spite of lower temperature rise. We analyzed the magnetizing process using two parameters, the “magnetic flux penetration ratio,” Rin, and the “magnetic flux residual ratio,” Rout, for various pulse sequences for the split-type and solenoid-type coils. The Rin value was decreased by the double-PFM for both coils, and the Rout value was improved only by the double-PFM using the solenoid-type coil. As a result, the trapped field for single-PFM using the split-type coil, which has a higher Rin, reduced after the double-PFM due to a decrease of Rin and no enhancement of Rout. These results are in clear contrast to those using the solenoid-type coil.