Temperature rise in an Sm-based bulk superconductor after applying iterative pulse fields

The time evolutions and spatial distributions of temperature rise ΔT(t) have been measured on the surface of a cryo-cooled SmBaCuO bulk superconductor after iterative pulse field magnetizing with the same amplitude. For the applied pulse field B_ex ≤ 4.64 T, the maximum temperature rise ΔT_max monotonically decreases and approaches a steady ΔT(t) behaviour with an increasing number of times of pulse applications. On the other hand, for B_ex = 5.42 T, ΔT_max keeps on increasing after the third pulse application in a specific growth sector region and a clear anisotropic ΔT (t) behaviour has been found. The magnetic fluxes preferentially enter and leave the bulk superconductor through this sector region. The ΔT(t) behaviours are closely correlated with the distribution of the trapped field B_T^P and can be understood on the basis of the heat generation caused by the flux motion.