A hydrothermal route to single crystals of rare earth stannates RE₂Sn₂O₇ (RE = La–Lu) in the cubic pyrochlore structure is reported. Growth reactions were performed in aqueous fluids at 700 °C and 200 MPa with CsF mineralizers in concentrations ranging from 0 to 30 M, with 20 M CsF providing the most consistent results. Single crystals of the entire range of lanthanides were grown and characterized by single crystal X-ray diffraction and found to be isostructural in the Fd3̅m space group. The unit cell sizes range from 10.7106(16) Å for La₂Sn₂O₇ to 10.3005(9) Å for Lu₂Sn₂O₇. Both the unit cell size and RE–O distances are found to be essentially linear with respect to the ionic radius of the rare earth ion. The high quality diffraction data strongly suggests that there is very little site disorder or lattice defects in the sample. Of particular interest is the synthesis and single crystal growth of Ce₂Sn₂O₇, which represents one of the few f¹ pyrochlore samples. Specific heat measurements were obtained down to 50 mK on both Yb₂Sn₂O₇ and Ce₂Sn₂O₇, with the Yb material displaying a single sharp peak at 138 mK suggesting that the sample does not contain any site disorder or “lattice stuffing”. The Ce analog shows only a broad featureless transition below 100 mK, with this lack of long-range magnetic order consistent with quantum spin liquid behavior.

中文翻译：

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稀土锡立方四氯稀土，RE ₂ Sn ₂ O ₇（RE = La–Lu）的水热晶体生长：有序有序，低缺陷的单晶

据报道，在立方烧绿石结构中，一条热液途径生成了稀土锡酸盐RE ₂ Sn ₂ O ₇（RE = La-Lu）单晶。生长反应是在700°C和200 MPa的水性流体中，使用浓度范围为0到30 M的CsF矿化剂进行的，其中20 M CsF提供最一致的结果。镧系元素的整个范围内的单晶生长和表征通过单晶X射线衍射，结果为中等结构的Fd 3米的空间群。单位晶格尺寸范围从La ₂ Sn ₂ O _7的10.7106（16）Å到Lu ₂ Sn ₂ O的10.3005（9）Å₇。发现晶胞大小和RE–O距离相对于稀土离子的离子半径基本上是线性的。高质量的衍射数据强烈表明样品中几乎没有位错或晶格缺陷。特别令人感兴趣的是Ce ₂ Sn ₂ O ₇的合成和单晶生长，它是少数f ¹烧绿石样品之一。在Yb ₂ Sn ₂ O ₇和Ce ₂ Sn ₂ O ₇上均获得了低至50 mK的比热测量值，Yb材料在138 mK处显示一个尖锐的峰，表明该样品不包含任何位错或“晶格填充”。Ce模拟物在100 mK以下仅显示出宽广的无特征跃迁，缺乏与量子自旋液体行为一致的长距离磁阶。