Phase diagram and superconductivity at 58.1 K in α-FeAs-free SmFeAsO1-xFx

M. Fujioka, S. J. Denholme, T. Ozaki, H. Okazaki, K. Deguchi, S. Demura, H. Hara, T. Watanabe, H. Takeya, T. Yamaguchi, H. Kumakura, Y. Takano

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63 Citations (Scopus)


The phase diagram of SmFeAsO1-xFx in terms of x is exhibited in this study. Specimens of SmFeAsO1-xFx from x = 0 to x = 0.3 were prepared by low-temperature sintering with slow cooling. The low-temperature sintering suppresses the formation of the amorphous FeAs, which is inevitably produced as an impurity when using high-temperature sintering. Moreover, slow cooling is effective in obtaining a high fluorine concentration. The compositional change from feedstock composition is quite small after this synthesis. We can reproducibly observe a record superconducting transition for an iron-based superconductor at 58.1 K. This achievement of a high superconducting transition is due to the success in substituting a large amount of fluorine. A shrinking of the a lattice parameter caused by fluorine substitution is observed and the substitutional rate of fluorine changes at x = 0.16.

Original languageEnglish
Article number085023
JournalSuperconductor Science and Technology
Issue number8
Publication statusPublished - Aug 2013
Externally publishedYes


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