Hydrothermal Synthesis, Structure, and Superconductivity of Simple Cubic Perovskite (Ba0.62K0.38)(Bi0.92Mg0.08)O3 with Tc ∼ 30 K.
Hydrothermal Synthesis, Structure, and Superconductivity of Simple Cubic Perovskite (Ba0.62K0.38)(Bi0.92Mg0.08)O3 with Tc ∼ 30 K.
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DOI：
10.1021/acs.inorgchem.6b01853
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发表时间：
2017-02
影响因子：
4.6
通讯作者：
Mirza H. K. Rubel;T. Takei;N. Kumada;M. M. Ali-M.;A. Miura;K. Tadanaga;K. Oka;M. Azuma;E. Magome;C. Moriyoshi;Y. Kuroiwa
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文献类型：
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作者：
Mirza H. K. Rubel;T. Takei;N. Kumada;M. M. Ali-M.;A. Miura;K. Tadanaga;K. Oka;M. Azuma;E. Magome;C. Moriyoshi;Y. Kuroiwa
我们采用水热法在220 °C合成了一种新型的钙钛矿型超导氧化铋。起始材料的选择、它们的混合比和水热反应温度对于获得具有上级超导性能的产品至关重要。使用实验室X射线衍射、高分辨率同步加速器X射线衍射（SXRD）数据和电子衍射（艾德）图案[透射电子显微镜（TEM）分析]研究粉末样品的结构。SXRD数据的细化证实了具有a = 4.27864（2）<$[空间群Pm 3 <$m（No.221）]的立方晶胞的简单钙钛矿型结构。元素分析检测到镁在最终产品中，并基于SXRD和电感耦合等离子体数据的细化产生了理想的未扭曲的简单立方钙钛矿型结构，其化学组成为（Ba0.62K0.38）（Bi0.92Mg0.08）O3。艾德图也证实了简单的立方钙钛矿结构;立方形的微观结构和纳米尺度上的成分均匀性分别通过扫描电子显微镜和TEM分析进行了验证。所制备的化合物表现出约98%的大屏蔽体积分数，最大Tcmag为1.30 K，这是由测量的铋价，以及支持。其电阻率在1021 K时下降，在7 K以下电阻率为零.该化合物在400 °C以上发生热分解。最后，计算的能带结构显示了这种水热合成的氧化铋的金属行为。
We have synthesized a new superconducting perovskite bismuth oxide by a facile hydrothermal route at 220 °C. The choice of starting materials, their mixing ratios, and the hydrothermal reaction temperature was crucial for obtaining products with superior superconducting properties. The structure of the powder sample was investigated using laboratory X-ray diffraction, high-resolution synchrotron X-ray diffraction (SXRD) data, and electron diffraction (ED) patterns [transmission electron microscopy (TEM) analysis]. The refinement of SXRD data confirmed a simple perovskite-type structure with a cubic cell of a = 4.27864(2) Å [space group Pm3̅m (No. 221)]. Elemental analysis detected magnesium in the final products, and a refinement based on SXRD and inductively coupled plasma data yielded an ideal undistorted simple cubic perovskite-type structure, with the chemical composition (Ba0.62K0.38)(Bi0.92Mg0.08)O3. ED patterns also confirmed the simple cubic perovskite structure; the cube-shaped microstructures and compositional homogeneity on the nanoscale were verified by scanning electron microscopy and TEM analyses, respectively. The fabricated compound exhibited a large shielding volume fraction of about 98% with a maximum Tcmag of ∼30 K, which was supported by the measured bismuth valence as well. Its electrical resistivity dropped at ∼21 K, and zero resistivity was observed below 7 K. The compound underwent thermal decomposition above 400 °C. Finally, the calculated band structure showed a metallic behavior for this hydrothermally synthesized bismuth oxide.