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2008/05/28(Wed) 12:08

Vortex Pinning State on RE123 Films with c-axis Correlated Disorders



We study the vortex pinning state for REBa2Cu3Ox (RE123,RE: rare-earth) films with various kinds of c-axis correlated pinning. In case of the LTG-Sm123 film, the peak around B//c (θ = 0˚) in the angular dependence of Jc shrinks and almost disappears with increasing a magnetic field but it grows again with further increasing of a magnetic field at various temperatures as shown in the insets of the figure. As a result, the complex vortex pinning state diagram can be described schematically as shown in the figure. In addition, we also found that the vortex pinning state diagram strongly depends on a sort of the c-axis correlated disorders such as columnar shaped precipitates, edge dislocations or columnar defects by fission track and so on.

IMR, Tohoku University: S. Awaji, M. Namba, K. Watanabe
Dep. of Elect. Eng. Sci., Nagoya University: Y. Yoshida
Dep. of Mat. Sci., Kyushu Institute of Technology: K. Matsumoto

Reference: S. Awaji, N. Namba, K Watanabe, M. Miura, Y. Yoshida, Y. Ichino, Y. Takai and K. Matsumoto,
"c-axis correlated pinning behavior near the irreversibility fields",
Appl. Phys. Lett. 90 (2007) 122501.

様々なc軸相関ピンニングを有するREBa2Cu3Ox (RE123, RE: rare-earth)膜における,磁束ピンニング状態を調べた.LTG-Sm123膜の場合,挿入図に示すように,c軸相関ピンに由来するJcの角度依存性におけるB//c (θ = 0˚)近傍のピークは,磁場の増加と共に一旦消滅した後,不可逆磁場近傍で再度増加することが分かった.この結果から,図のような磁束ピンニング状態図が描かれる.さらに,この磁束ピンニング状態図は,c軸相関ピンの種類によって大きく変化すること見出した.

東北大学金属材料研究所:淡路 智,難波雅史,渡辺和雄
名古屋大学工学部:吉田 隆
九州工業大学工学部:松本 要