Crystal structure and superconductivity of FeSr₂YCu₂O_6+y superconductor

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• 作者：Yoshiaki Hata ; Kazufumi Watanabe ; Takashi Mochiku ; Hiroshi Yasuoka
• 关键词：High- ; none ; color ; black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6TVJ-4XVBP7J-8&_mathId=mml21&_pii=S0921453409008855&_issn=09214534&_acct=C000060114&_version=1&_userid=3259313&md5=b54b64ad708ac4243844
• 刊名：Physica C
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：470
• 期：Supplement 1
• 页码：S92-S93
• 全文大小：178 K

文摘

FeSr₂YCu₂O_6+y compound (YFe1212) exhibits superconductivity only when it is annealed in a N₂ flow and subsequently in an O₂ flow. To study the relation between the superconductivity and oxygen content, 6+y, YFe1212 with various oxygen contents (6+y=6.88–7.55) were synthesized and their crystal structures, magnetism and superconductivity were studied. After the annealing in N₂ flow, the oxygen content, 6+y, was 6.88 and the crystal structure was orthogonal. Increasing the oxygen content, lattice constant decreased monotonically and the crystal structure changed to tetragonal at around the oxygen content 6+y=7.10. Superconductivity was observed above the oxygen content 6+y=7.30 and the onset superconducting transition temperature increased up to 53 K with the oxygen content 6+y=7.55. Increasing the oxygen content, the bond valence sum of Cu ion increased and it coincides with the result of the susceptibility measurement. In all samples, anomalies are observed at 12 K and they seems to be magnetic transition of Fe ion. The magnetic transition temperatures are independent of the oxygen content, 6+y.