Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO1-xFxFeAs.
A series of layered CeO1-xFxFeAs compounds with x=0 to 0.20 are synthesized by the solid state reaction method. Similar to the LaOFeAs, the pure CeOFeAs shows a strong resistivity anomaly near 145 K, which was ascribed to the spin-density-wave instability. F doping suppresses this instability and leads to the superconducting ground state. Most surprisingly, the superconducting transition temperature could reach as high as 41 K. Such a high T_{c} strongly challenges the classic BCS theory based on the electron-phonon interaction. The closeness of the superconducting phase to the spin-density-wave instability suggests that the magnetic fluctuation plays a key role in the superconducting pairing mechanism. The study also reveals that the Ce 4f electrons form local moments and are ordered antiferromagnetically below 4 K, which could coexist with superconductivity.
Chen
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GF
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Li
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Wu
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Li
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Hu
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Dong
J
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Zheng
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Luo
J L
JL
Wang
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