Superconducting and structural properties of nearly carbonate-free HgBa2CuO4+δ

Ayako Yamamoto, Wei Zhi Hu, Fujio Izumi, Setsuko Tajima

研究成果: Article査読

11 被引用数 (Scopus)


Nearly carbonate-free HgBa2CuO4+δ (Hg-1201) was prepared from high-purity starting materials BaO, HgO and CuO. We heated BaCO3 at different temperatures to optimize conditions of producing BaO. The residual carbon content in the purified BaO is less than 0.1 at.%. With the high-purity BaO, we could raise the temperature of sintering Hg-1201, which led to a higher Tc, a sharper superconducting transition and good crystallinity. An optimally doped sample showed a Tc of 98.0 K in susceptibility and 97.0 K in resistivity (zero-resistance). By changing the annealing condition carefully, samples with a wide range of doping levels were obtained without degradation, and their superconducting properties were studied. Rietveld refinement of neutron powder diffraction data for an optimally doped sample revealed a slight deficiency in [O-Hg-O]2- groups, giving a chemical formula of Hg0.970Ba2CuO4.059 (CO3)0.0088. This defect structure model provides a hole concentration, p, of 0.20 which is a more reasonable value than p=0.25 obtained in our previous model on the assumption of a stoichiometric cation composition.

ジャーナルPhysica C: Superconductivity and its applications
出版ステータスPublished - 2001 4月 15

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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