The recently discovered quaternary arsenide oxide superconductor La[O1-xFx]FeAs with the superconducting critical transition temperature (Tc) of 26 K [1], has been quickly expanded to another high-Tc superconducting system beyond copper oxides by the replacement of La with other rare earth elements, such as Sm, Ce, and Pr etc. [2-4], and the Pr[O1-xFx]FeAs has become to be the first non-cuprate superconductor that holding a Tc above 50 K. All these arsenide (including phosphide) superconductors formed in a same tetragonal layered structure with the space group P4/nmm which has an alternant stacked Fe-As layer and RO (R = rare earth metals) layer. Here we report the discovery of another superconductor in this system, the neodymium-arsenide Nd[O1-xFx]FeAs with an resistivity onset Tc of 51.9 K, which is the second non-cuprate compound that superconducts above 50 K.
@article{arxiv.0803.4234,
title = {Superconductivity in iron-based F-doped layered quaternary compound Nd[O1-xFx]FeAs},
author = {Zhi-An Ren* and Jie Yang and Wei Lu and Wei Yi and Xiao-Li Shen and Zheng-Cai Li and Guang-Can Che and Xiao-Li Dong and Li-Ling Sun and Fang Zhou and Zhong-Xian Zhao*},
journal= {arXiv preprint arXiv:0803.4234},
year = {2009}
}