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arXiv · 1903.00866

Large and significantly anisotropic critical current density induced by planar defects in CaKFe4As4 single crystals

Sunseng Pyon·Ayumu Takahashi·Ivan Veshchunov·Tsuyoshi Tamegai·Shigeyuki Ishida·Akira Iyo·Hiroshi Eisaki·Motoharu Imai·Hideki Abe·Taichi Terashima·Ataru Ichinose
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Abstract

Three independent components of critical current density, one for the H//c axis and the other two for the H//ab plane, have been studied in CaKFe4As4 single crystals. When the magnetic field is applied along the c axis, we observed fish-tail-like peaks in the M-H hysteresis loop, and the magnetization at higher temperatures exceeds that at lower temperatures at high fields. When the field is applied parallel to the ab plane, a dip structure is observed in the M-H hysteresis loop near the self-field. In addition, for the H//ab plane, we succeeded in separately evaluating the large and significantly anisotropic in-plane and out-of-plane Jc. Transmission electron microscopy revealed the presence of planar defects parallel to the ab plane in CaKFe4As4, which have not been observed in any other iron-based superconductors. We discuss the possible relationship between the anomalous Jc behavior and the planar defects.

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Sunseng Pyon, Ayumu Takahashi, Ivan Veshchunov, Tsuyoshi Tamegai, Shigeyuki Ishida, Akira Iyo, Hiroshi Eisaki, Motoharu Imai, Hideki Abe, Taichi Terashima, Ataru Ichinose. 2019-03-05. Large and significantly anisotropic critical current density induced by planar defects in CaKFe4As4 single crystals. https://doi.org/10.1103/physrevb.99.104506

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