Experimental verification of the magnetic flux penetration property and flux flow inhibition effect of a superconducting bulk magnet with small holes

We have proposed that GdBa₂Cu₃O_7-x bulk material with small holes can easily be magnetized by pulsed-field magnetization. When the fundamental experiment of applying a single pulsed field with various amplitudes was carried out, the total magnetic flux sharply increased in a low applied field, and flux reduction caused by flux flow hardly occurred in a high applied field. In this paper, we investigate the cause of these effects by using trapped field distributions to calculate current densities in the regions with and without holes. The value of the region with holes was about 10% greater, implying that suppression of flux flow created enhancement of the current density by small holes.