Controlled synthesis of the antiperovskite oxide superconductor Sr3-xSnO
Controlled synthesis of the antiperovskite oxide superconductor Sr3-xSnO
复制标题
反钙钛矿氧化物超导体Sr3-xSnO的控制合成
DOI：
10.1088/1361-6668/aab6c2
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发表时间：
2018
影响因子：
3.6
通讯作者：
Maeno Y
中科院分区：
文献类型：
--
作者：
Hausmann J N;Oudah M;Ikeda A;Yonezawa S;Maeno Y
已知多种钙钛矿氧化物超导体，包括一些最突出的高温和非常规超导体。然而，最近首次报道了氧化态反转材料类别（反钙钛矿氧化物）的超导电性。在这种超导体Sr 3− x SnO中，实现了非常规的离子态Sn 4−，并讨论了由于能带反转而可能的非常规超导性。在这里，我们讨论了一种改进的简易合成方法，使其有可能控制Sr 3− x SnO中的锶缺乏。此外，还提出了一种在熔点以上合成Sr 3SnO的方法.我们证明了超导锶缺乏Sr 3− x SnO（Tc ≤ 5 K）和Sr 3 SnO的磁化强度和电阻率的温度依赖性，在交流磁化率下降到0.15 K时没有超导转变。此外，我们揭示了锶原料纯度对超导性的显著影响，并实现了与迄今为止报道的最高值相比大幅增加的M/M Meissner（1）。利用粉末X射线衍射和能量色散X射线光谱进行的更详细的表征表明，一个次要的立方相是SrO，以前认为是另一个晶格参数稍大的Sr 3− x SnO相。本文报道的改进的表征和受控合成使得能够详细研究Sr 3− x SnO中的超导性质及其对锶缺乏的依赖性。
A large variety of perovskite oxide superconductors are known, including some of the most prominent high-temperature and unconventional superconductors. However, superconductivity among the oxidation state inverted material class, the antiperovskite oxides, was recently reported for the first time. In this superconductor, Sr 3− x SnO, the unconventional ionic state Sn 4− is realized and possible unconventional superconductivity due to a band inversion has been discussed. Here, we discuss an improved facile synthesis method, making it possible to control the strontium deficiency in Sr 3− x SnO. Additionally, a synthesis method above the melting point of Sr 3 SnO is presented. We show temperature dependence of magnetization and electrical resistivity for superconducting strontium deficient Sr 3− x SnO (T c∼ 5 K) and for Sr 3 SnO without a superconducting transition in alternating current susceptibility down to 0.15 K. Further, we reveal a significant effect of strontium raw material purity on the superconductivity and achieve substantially increased M/M Meissner (∼ 1) compared to the highest value reported so far. More detailed characterizations utilizing powder x-ray diffraction and energy-dispersive x-ray spectroscopy show that a minor cubic phase, previously suggested to be another Sr 3− x SnO phase with a slightly larger lattice parameter, is SrO. The improved characterization and controlled synthesis reported herein enable detailed investigations on the superconducting nature and its dependency on the strontium deficiency in Sr 3− x SnO.