Reactive sintering for oriented and connected Bi-2223 superconductive oxides from a mixture of delaminated Bi-2212 and fine powdered supplemental ingredients |
| |
Authors: | Masaru Nakamura Hiroshi Kutami and Yuh Shiohara |
| |
Institution: | a Superconductivity Research Laboratory, ISTEC, 1-10-13 Shinonome, Koto-ku, Tokyo 135, Japan b Research Laboratory of Material, Tokyo Institute of Technology, Nagatsuta 4259, Midori-ku, Yokohama-shi, Kanagawa 226, Japan |
| |
Abstract: | Single crystals of NdBa2Cu3O7−δ (Nd123) have been successfully grown by the top-seeded solution-growth (TSSG) method in 1%, 21% and 100% oxygen partial pressure atmosphere ((P(O2) = 0.01 atm, P(O)2) = 0.21 atm and P(O2) = 1.00 atm). Ba---Cu---O solvent with a Ba to Cu ratio of 3:5 was used in a Nd2O3 crucible. Nd is supplied by the reaction between the molten solvent and the Nd2O3 crucible. Compositions of Nd123 single crystals grown in different oxygen partial pressure atmospheres were analyzed by inductivity coupled plasma atomic emission spectrometry (ICP-AES) and confirmed to be Nd:Ba:Cu = 1.01:1.97:3.00 for P(O2) = 0.01 atm, Nd:Ba:Cu = 1.07:1.95:3.00 for P(O2) = 0.21 atm and Nd:Ba:Cu = 1.10:1.90:3.00 for P(O2) = 1.00 atm, respectively. The Nd123 single crystals grown in different oxygen partial pressure atmospheres were annealed in a pure oxygen gas flow, and the temperature dependence of the DC magnetization for these crystals was measured using a superconducting quantum interference device (SQUID) magnetometer. The Nd123 single crystal grown in P(O2) = 0.01 atm, and annealed at 340°C for 200 h showed a steep superconductive transition at 96 K. On the other hand, the Nd123 crystal grown in P(O2) = 0.21, 1.00 atm and, annealed at 340°C for 200 h exhibited a broad transition at 92 K for P(O2) = 0.21 atm and at 88 K for P(O2) = 1.00 atm, respectively. Therefore for Nd123 single crystal production with high quality superconductive characteristics, a low oxygen partial pressure atmosphere during crystal growth is found to be effective for minimizing the substitution of Nd ions into Ba sites. |
| |
Keywords: | Bi-2223 Delamination Green sheet densification Reactive sintering Quantitative analysis of texture |
本文献已被 ScienceDirect 等数据库收录! |
|