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| R&D History |
In the beginning of 1960's, SEI's research in superconductivity started from the research on metal superconductors wire materials that become superconductive in liquid helium. Although various high-temperature superconductive materials were discovered, today, bismuth and rare-earth superconductors are seen as the materials of choice for commercialization. Since discovery of these superconductive materials, SEI has been striving toward the development of applied products and fabrication of wires from bismuth and rare-earth superconductors.
Bismuth Superconductors
High-temperature superconductor composed of Bi (bismuth), Sr (strontium), Ca (calcium), Cu (copper), and O (oxygen) is called the bismuth high-temperature superconductor. The 2223 phase, with composition ratio of Bi, Sr, Ca and Cu is 2:2:2:3, has high critical temperature (110 K) and therefore since its discovery, is attracting much attention as a practicable material. Recent improvement in performance of bismuth (2223 phase) high-temperature superconductor has allowed the manufacture of larger-sized prototype cables and magnets of actual sizes needed in their respective applications.
Rare-Earth Superconductors
High-temperature superconductors composed of Re (rare earth), Ba (barium), Cu (copper) and O (oxygen) is called a rare-earth high-temperature superconductor. Rare earth components include Y (yttrium), Nd (neodymium), Sm (samarium), and Ho (holmium). The rare-earth high-temperature superconductors can synthesize the superconductors that are close to the monochrystals, and they have superior characteristics in critical current densities and in high magnetic fields.
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