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長村 光造*; 町屋 修太郎*; 梶原 堅太郎*; 川崎 卓郎; Harjo, S.; Zhang, Y.*; 藤田 真司*; 飯島 康裕*; Hampshire, D. P.*
AIP Advances (Internet), 9(7), p.075216_1 - 075216_11, 2019/07
被引用回数:7 パーセンタイル:38.09(Nanoscience & Nanotechnology)In the commercial coated conductor tapes, the twinned structure of REBCO (REBaCuO, RE = Y and Gd) is characterized as either 100 or 110 orientation based on the tape length direction. In this study, we investigate the effects of the two different twinned structures on the critical current of the REBCO tapes by combining; transport critical current and synchrotron radiation diffraction measurements. For the tapes with 100 oriented twins, we observed the inverted parabolic strain behavior on the uniaxial strain dependence of . In contrast, the ones with 110 oriented twins showed a weak strain behavior without any maximum appeared in the strain dependence. Such a different uniaxial strain dependence was analyzed by using the one-dimensional twin model with different fractional lengths of A-domains and B-domains of REBCO twins. This model explains the essential features of the different uniaxial strain dependence we observed.
長村 光造*; 町屋 修太郎*; Hampshire, D. P.*; 土屋 佳則*; 菖蒲 敬久; 梶原 堅太郎*; 長部 吾郎*; 山崎 浩平*; 山田 雄一*; 藤上 純*
Superconductor Science and Technology, 27(8), p.085005_1 - 085005_11, 2014/08
被引用回数:27 パーセンタイル:74.87(Physics, Applied)In order to explain the effect of uniaxial strain on the critical current of DI-BSCCO-Bi2223 tapes, we employed a springboard sample holder that can smoothly and continuously apply both tensile and compressive strains to tape samples. Over a narrow tensile strain region, the critical current in the tapes decreased linearly with increasing strain and returned reversibly with decreasing strain. In this paper, we clearly characterize the reversible range terminated by both compressive and tensile strains, in which filaments do not fracture. Our analysis of the compressive regime beyond the relaxation strain suggests that although BSCCO filament fracture is the primary factor that leads to a decrease in critical current, the critical current in those regions of filaments that are not fractured increases linearly and reversibly with decreasing applied strain at compressive strains well beyond the reversible region for the tape.
Carty, G. J.*; 町田 昌彦; Hampshire, D. P.*
Physical Review B, 71(14), p.144507_1 - 144507_9, 2005/04
被引用回数:13 パーセンタイル:50.02(Materials Science, Multidisciplinary)超伝導体にコーティングする金属の特性とともに超伝導体の磁化過程がどのように変化するかという問題は、超伝導体の磁場中での性質を制御するうえで極めて重要な問題であり、系統的な大規模数値シミュレーションにより初めて理解可能である。本研究では、この問題意識に答えるべく、超伝導体の超伝導電子密度の時空間発展を現象論的レベル(巨視的レベル)で記述する時間依存のギンツブルクランダウ方程式を数値的に解き、任意の電気抵抗を持つ金属をコーティングした超伝導体の磁気特性(磁化過程)を調べた。その結果、量子化磁束の侵入が金属の臨界温度や電気抵抗に強く依存することを初めて直接示すことに成功したほか、コーティングの膜厚依存性についても、定性的理解を得ることができた。