Control of carrier concentration in Bi-2212

S. Yamashita*, T. Kasai, T. Fujii, T. Watanabe, A. Matsuda


研究成果: Article査読

6 被引用数 (Scopus)


We realized highly underdoped Bi-2212 crystals by using a Bi substitution into a Sr site (x), together with the excess oxygen (δ) control. The samples with x = 0-0.3 were grown by a traveling solvent floating zone method. For each x, δ was varied using the precision annealing method [1]. Under several assumptions, the effective Bi valence was evaluated to be +2.2, which is much lower than the formal valence +3. This indicates that the Bi substitution accompanies additional uptake in excess oxygen. The x dependent δ-doping level p relation and the observed shrink in the c-axis length are consistent with this assumption. Based on the decomposition phase diagram obtained in this study, Tc of 22 K was realized by careful annealing treatments. The samples showed a superconducting volume fraction of over 50%.

ジャーナルPhysica C: Superconductivity and its applications
出版ステータスPublished - 2010 12月 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • エネルギー工学および電力技術
  • 電子工学および電気工学


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