Enhancement of the superconducting transition temperature of FeSe by intercalation of a molecular spacer layer
Enhancement of the superconducting transition temperature of FeSe by intercalation of a molecular spacer layer
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DOI：
10.1038/nmat3464
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发表时间：
2013-01-01
期刊：
影响因子：
41.2
通讯作者：
Clarke, Simon J.
中科院分区：
文献类型：
--
作者：
Burrard-Lucas, Matthew;Free, David G.;Clarke, Simon J.
层状砷化铁中高温超导电性的发现(1)导致了通过改变相邻阴离子砷化铁(2-7)层之间间隔层的化学成分来优化铁基超导体超导性能的深入研究。在具有由金属离子(例如，Li+，Na+，K+，Ba2+)或PbO-或钙钛矿型氧化层组成的阳离子间隔层的砷化铁中，以及在Fe1.01Se(参考文献)中都发现了超导电性。8)具有结构类似于砷化铁中的中性层，并且没有间隔层。在这里，我们展示了Li-x(NH_2)(Y)(NH_3)(1-y)Fe_2Se_2(x类似于0.6；y类似于0.2)的合成，锂离子，锂酰胺和氨作为FeSe层之间的隔离层，在43(1)K表现出比迄今报道的任何FeSe衍生化合物更高的超导电性。我们用中子粉末衍射法测定了它的晶体结构，并用磁测量和Muon自旋旋转数据确定了它的超导性质。这条新的合成路线为进一步开发该体系和其他体系中的相关分子插层提供了可能性，从而极大地优化了该家族的超导性能。
The discovery of high-temperature superconductivity in a layered iron arsenide(1) has led to an intensive search to optimize the superconducting properties of iron-based superconductors by changing the chemical composition of the spacer layer between adjacent anionic iron arsenide layers(2-7). Superconductivity has been found in iron arsenides with cationic spacer layers consisting of metal ions (for example, Li+, Na+, K+, Ba2+) or PbO- or perovskite-type oxide layers, and also in Fe1.01Se (ref. 8) with neutral layers similar in structure to those found in the iron arsenides and no spacer layer. Here we demonstrate the synthesis of Li-x(NH2)(y)(NH3)(1-y)Fe2Se2 (x similar to 0.6; y similar to 0.2), with lithium ions, lithium amide and ammonia acting as the spacer layer between FeSe layers, which exhibits superconductivity at 43(1) K, higher than in any FeSe-derived compound reported so far. We have determined the crystal structure using neutron powder diffraction and used magnetometry and muon-spin rotation data to determine the superconducting properties. This new synthetic route opens up the possibility of further exploitation of related molecular intercalations in this and other systems to greatly optimize the superconducting properties in this family.