| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Research Abstract |
For the practical applications of high-T_c superconductor bulks as a high-strength bulk magnet in a magnetic separation system and so on, the pulse field magnetization (PFM) technique has been intensively investigated because of the relatively compact, inexpensive and mobile setup of the apparatus, besides the static field-cooled magnetization (FCM). The trapped field B_T^P and the total trapped flux Φ_T^P by PFM are, however, generally smaller than those attained by FCM due to the large temperature rise ΔT caused by the magnetic flux motion against the vortex pinning force F_p and the viscous force F_v. In order to enhance the B_T^P and Φ_T^P values, the ΔT reduction is an indispensable issue. We have studied the time evolution and spatial distribution of the temperature rise ΔT(t) and the local field B_L(t) on the surface of the cryo-cooled REBaCuO bulks (RE=Gd,Y,Sm) during PFM for various starting temperatures T_s and the applied fields B_<ex>. We proposed a PFM technique named as modified multi-pulse technique with stepwise cooling (MMPSC) from the basic experimental results. We have attained the B_T^P as high as 5.20 T by the MMPSC method, which is the new highest record by PFM. This method is confirmed to be a promising and effective technique to enhance B_T^P using other superconducting bulks.
A new-type of magnet system using REBaCuO bulks has been developed, in which two or five aligned bulk disks are cooled down from the side face by thermal conduction and are magnetized along the c-axis in turn employing a split-type pulse coil. The trapped field B_T^P is B_T^<4mm>=1.97 T on the vacuum sheath, 4 mm above the bulk surface. This type of magnet system consisting of multi-bulks, with usable surfaces on both sides in open space has a potential for new application fields such as magnetic separation for the environmental cleaning and the drag delivery system.
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