Abstract
Using the solid state reaction method, we have synthesized the polycrystalline F-doped NdO0.88F0.12FeAs and CeO0.88F0.12FeAs with the superconducting transition temperatures at about 48 and 40 K, respectively. To obtain the upper critical field H c2 of Nd(Ce)O0.88F0.12FeAs samples, we measured the electrical resistivity under magnetic field up to 14 T. Based on the Werthamer-Helfand-Hohenberg (WHH) relation together with the H c2(T) curves in a relatively high field, we estimated that these superconductors have a rather high upper critical field of about 115 T for Nd-based and 107 T for Ce-based samples, indicating the similarities between these ReO1−x F x FeAs (Re = rare earth element) superconductors and high T c cuprate superconductors.
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Recommended by Prof. Nie Yuxin, Executive Editor of Science in China Series G-Physics, Mechanics & Astronomy
Supported by the National Basic Research Program of China (973 Program)(Grant No. 2006CB9213001) and the National Natural Science Foundation of China (Grant No. 10774181)
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Wu, D., Li, Z., Su, S. et al. Very high upper critical fields of F-doped Fe-based layered superconductors NdO0.88F0.12FeAs and CeO0.88F0.12FeAs. Sci. China Ser. G-Phys. Mech. Astron. 51, 715–718 (2008). https://doi.org/10.1007/s11433-008-0074-x
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DOI: https://doi.org/10.1007/s11433-008-0074-x