Superconductivity of (Hg0.7Tl0.3)2Ba2Y 1-xCaxCu2O8-δ (0 ≦ x ≦ 0.8) with a wide range of doping state

Ayako Tokiwa-Yamamoto, Tadashi Tatsuki, Seiji Adachi, Keiichi Tanabe

研究成果: Article査読

19 被引用数 (Scopus)


(Hg,Tl)-based cuprates with the nominal compositions of (Hg0.7Tl0.3)2Ba2Y 1-xCaxCu2O8-δ (0 ≦ x ≦ 1.0, every 0.1 step) were prepared under high pressure, and nearly single phases were obtained for the samples with 0 ≦ x ≦ 0.8. We systematically investigated their unit cell dimensions, DC susceptibility, electrical resistivity, oxygen content and copper valence as a function of Ca content, x. For the samples with x = 0-0.4, Tc, which was determined by DC susceptibility, increased from 12 K to 84 K with increasing x, while the samples with x = 0.5-0.8 exhibited a Tc decrease from 84 K to 40 K. This result indicates that the doping state of the samples can be extensively varied from underdoped to overdoped states by the Ca substitution. This variation in the doping states was also supported by the systematic change in the temperature dependence of the electrical resistivity. Oxygen analysis revealed that the copper valence gradually increased from 2.12 to 2.26 with increasing x from 0 to 0.8. The copper valence with the maximum Tc of 84 K in these samples was determined to be 2.18-2.19, which is comparable to the value for the optimum Tc in other high-Tc cuprates.

ジャーナルPhysica C: Superconductivity and its applications
出版ステータスPublished - 1996 9月 10

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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