We report on the introduction of columnar defects in Ba 1− x K x Fe 2 As 2 and BaFe 2 (As 1− x P x ) 2 single crystals via 1.2 GeV Pb irradiation. Scanning transmission electron microscopy analysis proves the formation of continuous defects along the ion tracks, with a diameter of about 3 nm, and a planar density compatible with the irradiation fluence. The twofold role of such defects, i.e. as pair breakers as well as pinning centers, is investigated by a microwave technique, allowing us to determine critical temperature T c , surface impedance and penetration depth λ L , and by magneto-optical imaging and superconducting quantum interference device magnetometry to evaluate the critical current density J c . The decrease of T c is quite modest and, together with λ ...

中文翻译：

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柱状缺陷在铁基超导体中的双重作用

我们报道了通过1.2 GeV Pb辐照在Ba 1-x K x Fe 2 As 2和BaFe 2（As 1-x P x）2单晶中引入柱状缺陷的情况。扫描透射电子显微镜分析证明沿离子径迹形成连续的缺陷，直径约3 nm，平面密度与辐照通量兼容。通过微波技术研究了此类缺陷的双重作用，即成对破坏者和钉扎中心，使我们能够确定临界温度T c，表面阻抗和穿透深度λL，并通过磁光成像和超导量子确定干涉仪磁力计以评估临界电流密度J c。T c的降低是相当适度的，并且与λ...