Phase diagram and superconductivity at 58.1 K in α-FeAs-free SmFeAsO1-xFx
Phase diagram and superconductivity at 58.1 K in α-FeAs-free SmFeAsO1-xFx
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DOI：
10.1088/0953-2048/26/8/085023
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发表时间：
2013-08-01
影响因子：
3.6
通讯作者：
Takano, Y.
中科院分区：
文献类型：
--
作者：
Fujioka, M.;Denholme, S. J.;Takano, Y.
给出了SmFeAsO1-xFx的x相图。采用低温慢冷烧结法制备了x=0~x=0.3的SmFeAsO1-xFx样品。低温烧结抑制了非晶态FeAs的形成，而非晶态FeAs在高温烧结时不可避免地会以杂质的形式产生。此外，缓慢冷却是获得高氟浓度的有效方法。合成后原料组成的变化很小。我们可以在58.1K重现地观察到铁基超导体的一个创纪录的超导转变。这种高超导转变的实现是由于成功地替代了大量的氟。观察到由氟取代引起的α晶格参数的收缩，并且在x=0.16时，氟的取代速率发生变化。
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.