- Synthesis of Yba2Cu3O7-y Superconductor using a Low Purity BaCO3 Powder
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Chan-Joong Kim, Soon-Dong Park, Jung-Suk Choi, Byung-Hyuk Jun, Jong-Baik Moon, Sang-Heon Lee, Tae-Hyun Sung
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J Korean Powder Metall Inst. 2008;15(1):6-12.
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DOI: https://doi.org/10.4150/KPMI.2008.15.1.006
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 Abstract
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- [ YBa_2Cu_3O_7-y ](123) powders were synthesized by the solid state reaction method using two different purity BaCO_3 powders (99.75% and 99.7% purity) and Y_2O_3 (99.9%) and CuO (99.9%) powders. The effect of BaCO_3 purity on the formation of a 123 phase and the superconducting properties were investigated. The mixtures of raw powders were calcined at temperature ranges of 800°C-880°C in air and finally made into a single grain samples by a melt processing with top seeding. It was found that a 123 phase was well formed at temperature above 870°C, but the purity effect on the 123 formation was negligible. The single-grain 123 samples prepared from the different BaCO_3 powders showed the same T_c value of 90.5 K and similar J_c values about 104;A/cm2 at 0 T and 77 K, and 103;A/cm2 at 2 T and 77 K. This result indicates that the low purity, cheap price BaCO_3 powder can be used as a raw material for the fabrication of single-grain, high-J_c superconducting levitator.
- Occurrence Mechanism of Magnetic Properties in BiSrCaCuO Superconductor
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Sang-Heon Lee
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J Korean Powder Metall Inst. 2006;13(6):439-444.
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DOI: https://doi.org/10.4150/KPMI.2006.13.6.439
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Abstract
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- An electromagnetic properties in BiSrCaCuO superconductor were studied. In the measurement of current-voltage properties, the voltage was measured when applying an external magnetic field. The voltage continues to appear after the removal of the magnetic field. This phenomenon was considered as a nonvolatile magnetic effect. The voltage increased with the applied magnetic flux, but it became constant at about 10-2T. The appearance of the voltage was ascribed to the trapping of magnetic flux.
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