Studies of upgrading of its performance and magnetization technique of Ag-bearing Sm123-type superconducting permanent magnet materials

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The present work aims at developing c-axis oriented large Sm123 bulk superconductors and constructing a face-to-face-type magnetic field generator capable of producing magnetic field of more than 2 Tesla in open space, which is roughly 10 times larger than the magnetic field produced by ordinary Nd-Fe-B magnet.( 1 ) In 1999, we could develop Ag-bearing Sm123 superconductors with 36 mm in diameter and achieved a maximum trapped field of 3.8 Tesla on its surface by pulsed field at 30 K cooled by the refrigerator. We could successfully analyze the motion of quantized magnetic fluxes penetrated into the Sm123-superconductor upon the operation of a pulsed field at temperatures 30-77 K.( 2 ) The Ag-bearing Sm123 superconductor was also magnetized by static field up to 6.7 Tesla on its surface. By utilizing this strong field, we could fully magnetize the Nd-Fe-B plate with the dimension 50x50x0.5 mm by scanning it over the magnetic field thus produced. This was reported in Chunichi Newspaper … More on November 18, 1999.( 3 ) In 2000, we constructed a face-to-face-type magnetic field generator by mounting two almost identical Ag-bearing Sml23 superconductors with 36 mm in diameter, which were cooled to 35 K by a refrigerator. These two superconductors were magnetized by pulsed field. The trapped field of 2.8 Tesla was obtained in the air gap of 2mm sandwiched by these two superconductors. This was reported in Nikkan-Kogyo Newspaper on January 24, 2000. This demonstrated the opening of a new era in which we can use strong magnetic field exceeding 2 Tesla in open space.( 4 ) In January 2002, the Ag-bearing Sm 123 superconductor with the diameter of 60 mm was successfully synthesized. The installation of these two large superconductors into the field generator could produce the magnetic field of 3.0 Tesla in the air gap of 5mm, further strengthening our proposal concerning the availability ofa very strong magnetic field exceeding 2 Tesla by using the large bulk superconductors with a high trapped field performance. Less