Crystal growth of Ba2Can?1CunO2n(O,F)2 (n = 3 and 4) multi-layered superconductors under high pressure
Crystal growth of Ba2Can?1CunO2n(O,F)2 (n = 3 and 4) multi-layered superconductors under high pressure
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DOI：
10.1088/0953-2048/17/1/025
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发表时间：
2004
影响因子：
3.6
通讯作者：
A. Iyo;M. Hirai;K. Tokiwa;Tsuneo Watanabe;Y. Tanaka
中科院分区：
文献类型：
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作者：
A. Iyo;M. Hirai;K. Tokiwa;Tsuneo Watanabe;Y. Tanaka
多层超导体Ba 2Can − 1CunO 2n（O，F）2（F-02（n − 1）n，n = 3和4）的单晶在4.5 GPa的压力下生长。通过将标称成分为Ba 2Can − 1CunO 2nF 2（n = 2、2.5、3和4）的样品冷却至熔点，获得晶体。晶体是薄板状形状，典型尺寸为500 µm平面长度和30 µm厚度。发现晶体显示解理，这将便于表面灵敏测量。F-0223和F-0234晶体在氧退火后分别显示90 K和70 K的Tc。电阻率的温度依赖性表现出明显的欠掺杂行为。成分分析表明Ba：Ca：Cu的比例接近化学计量组成。我们认为F-体系是一种罕见的多层结构铜氧化物，它可以在高压下大量生长，它的晶体对研究高温超导和多层结构体系都是很有价值的。
Single crystals of multi-layered superconductors of Ba2Can−1CunO2n(O,F)2 (F-02(n − 1)n, n = 3 and 4) have been grown under a pressure of 4.5 GPa. Crystals were obtained by cooling samples with nominal compositions of Ba2Can−1CunO2nF2 (n = 2, 2.5, 3 and 4) across the melting point. The crystals are thin plate-like shapes with typical sizes of 500 µm in plane length and 30 µm in thickness. The crystals are found to show cleavage, which will be convenient for surface sensitive measurements. The F-0223 and F-0234 crystals showed Tc of 90 K and 70 K, respectively after oxygen annealing. The temperature dependence of resistivity showed pronounced underdoped behaviour. Composition analysis showed that a ratio of Ba:Ca:Cu is close to the stoichiometric composition one. We think that the F-system is a rare multi-layered cuprate that can largely grow under high pressure and its crystals are quite valuable to study both high-Tc superconductivity and the multi-layered system.