Flux-invading behaviors and temperature changes in Dy123 bulk magnet in iterative pulse field magnetization process

The flux invasion behaviors into the Dy123 based on HTS bulk magnet were precisely measured during the iterative pulsed field magnetizations operated at 31 K. The values of magnetic flux densities were measured at various positions on the bulk magnet sample during and after six successive applications of a peak applied field of 5T. The temperature changes were measured on the sample surface to compare them to the magnetic flux motions in the same manner. The invading flux were apparently repelled by the remaining trapped flux due to the former field application, and the domain where the magnetic flux reached was pushed back outward the sample with increasing the pulse number. The heat generation decreased with the iteration of field applications as well as the magnetic flux invasion expressing the same behavior, and saturated by the sixth field application. The time evolution of temperature measured at various positions on the sample surface showed that the heat generation occurs at the periphery of the sample and propagates toward the center of the sample.