| 摘要 |
PROBLEM TO BE SOLVED: To suppress unevenness of magnetic flux density distribution generated caused by enlargement by setting the uniformity of a superconductor consisting of a composite oxide of RE, Ba and Cu to a specified value or less. SOLUTION: Of the equivalent curve corresponding to a magnetic flux density of 0.6×Bm with respect a to surface maximum magnetic flux density Bm near the center and the distance to the magnetic flux maximum position corresponding to the surface magnetic flux density distribution for the upper surface or bottom surface of a bulk body, the uniformity is defined as tB/tA, when the minimum value in the direction of in-plane [100] or [010] or ReBa2 Cu3 O7-x phase 123 phase crystal equivalent thereto is set to tA, and the maximum value in the direction of in-plane [110] or [-110] or 123 phase crystal direction equivalent thereto is set to tB. In a bulk superconductor consisting of a disc or cylinder having a sectional circle diameter of 50 mm or more and less than 70 mm, the uniformity is set to 1.1 or less. In a bulk superconductor consisting of a disc or cylinder having a sectional circle diameter of 70 mm or more, the uniformity is set to 1.3 or less.
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