Generated heat during pulse field magnetizing for REBaCuO (RE = Gd, Sm, Y) bulk superconductors with different pinning abilities

Pulse field magnetizing (PFM) using five successive magnetic pulses (Nos 1-5) with the same amplitude from 3.01 to 5.42 T has been performed for three types of cryo-cooled REBaCuO bulk superconductor discs (RE = Gd, Sm, Y) with an identical size. The time evolution and spatial distribution of temperature T(t), the total trapped magnetic flux φ_T^P and the trapped magnetic field B_T^P have been measured after applying the magnetic pulse. The total magnetic flux φ_T^FC trapped by the field cooled magnetizing (FCM) is the largest for the Gd bulk and is the smallest for the Y bulk. The time and position dependences of T(t) during PFM show a characteristic behaviour depending on the species of bulks which results from the difference in the strength of the pinning force F_p. The generated heat Q(No i) after the No i pulse has been estimated based on the maximum temperature rise ΔT_max and the specific heat C. The ΔQ = Q(No 1)-Q(No 5) value, which is mainly contributed by the pinning power loss (Q_p) for pulse No 1, is the smallest for the Y bulk, and the Q(No 5) value, which is mainly contributed by the viscous flow loss (Q _v), is the smallest for the Gd bulk. These results suggest that the heat generation by PFM is closely related to the strength of F_p of the bulk crystal.