Characterization of a Large-Scale Nondoped YBa2Cu3O7−x Superconductor Prepared by Plastic Forming Without High-Pressure Molding |
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| Authors: | Makoto Takahashi Yuuko Tomioka Toshiyuki Miyauchi Shoji Sato Asami Murai Toshiyuki Ido Koichi Wakita Hiroshi Terada Sadao Ohkido Masanori Matsubara |
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| Affiliation: | Department of Applied Chemistry, College of Engineering, Chubu University, Aichi 487-8501, Japan; Department of Electronic Engineering, College of Engineering, Chubu University, Aichi 487-8501, Japan; Department of Natural Science and Mathematics, College of Engineering, Chubu University, Aichi 487-8501, Japan; Shinko Yogyou Co. Ltd., Gifu 509-5312, Japan |
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| Abstract: | A slurry containing YBa2Cu3O7? x particles and a fine YBa2Cu3(OH) x colloid solution was prepared, and a large-scale bulk YBa2Cu3O7? x superconductor (about 50 mm × 35 mm × 2 mm) was produced by plastic forming without high-pressure molding. The samples molded from the slurry were dried and then fired at 1223 K in air. X-ray diffraction data indicated that the samples had the characteristic orthorhombic YBa2Cu3O7? x structure. Measurements of electrical resistance were carried out between 300 and 50 K by the standard four-probe DC electrical measurement. The samples began superconducting at an onset temperature around 92 K, and the full-transition temperature (critical temperature) ( T c) was 88.7±1.4 K. The critical current density ( J c) measured at 77 K was about 440 A/cm2, the value of J c was improved by the heat treatment under an oxygen atmosphere, and J c=1.6 × 103 A/cm2 was observed. Under the magnetic field (B=1 T), the sample held its superconductivity, and demonstrated that this method can be used to produce the magnetic shielding used in magnetic resonance imaging diagnosis. |
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