The formation of nano-layered grains and their enhanced superconducting transition temperature in Mg-doped FeSe0.9 bulks.
The formation of nano-layered grains and their enhanced superconducting transition temperature in Mg-doped FeSe0.9 bulks.
复制标题
Mg掺杂FeSe0.9块体中纳米层状晶粒的形成及其增强的超导转变温度
DOI：
10.1038/srep06481
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发表时间：
2014-09-26
影响因子：
4.6
通讯作者：
Dou SX
中科院分区：
文献类型：
--
作者：
Lan F;Ma Z;Liu Y;Chen N;Cai Q;Li H;Barua S;Patel D;Al Hossain MS;Kim JH;Dou SX
寻找合适的掺杂剂来进一步提高11型铁基超导体的超导性对于其超导机制和可能的技术应用都有意义。在目前的工作中，通过两步固相反应方法获得了镁掺杂的 FeSe 多晶块体。尽管镁重掺杂 FeSe 块体中存在许多 MgSe 和铁杂质，但与未掺杂 FeSe 样品相比，它们的 Tc 明显增加。结果发现，Mg的添加对超导β-FeSe的晶格参数影响不大，但却形成了由MgSe和β-FeSe组成的纳米层状晶粒结构，且具有相似的X射线衍射特性。这种均匀层状晶粒结构中形成的 FeSe 和 MgSe 之间的大量纳米结构界面对超导性能具有显着影响，并且有助于 Tc 的增强，就像某些特定基底上的 FeSe 薄膜的情况一样。我们的工作不仅展示了提高块体超导体 Tc 的有效方法，而且还为考虑界面效应的非常规超导机制的系统研究提供了明确的平台。
To search a proper dopant to further improve superconductivity in 11 type Fe-based superconductors makes sense to both their superconductivity mechanism and possible technological applications. In present work, Mg doped FeSe polycrystalline bulks were obtained by a two-step solid-state reaction method. Even though there are many MgSe and iron impurities existing in the Mg heavy doped FeSe bulks, they exhibit obviously increased Tc compared to undoped FeSe sample. It was found that Mg addition has little effect on the crystal lattice parameters of superconducting β-FeSe, whereas leads to the formation of nano-layered grain structure consisted of MgSe and β-FeSe with similar X-ray diffraction characteristics. Lots of nano-structural interfaces between FeSe and MgSe formed in this homogenous layered grain structure have significant effect on the superconducting properties and are responsible for the enhancement of Tc, as like the case of FeSe thin film on some specific substrates. Our work not only demonstrates a powerful way for raising Tc in bulk superconductors, but also provides a well-defined platform for systematic studies of the mechanism of unconventional superconductivity by considering interface effect.