Synthesis of HgBa2Can-1CunO2(n+1)+d (n = 1,2,3) using high-purity BaO

Ayako Yamamoto, Wei Zhi Hu, Setsuko Tajima

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Abstract

Effects of carbon or carbonate impurity in the starting material BaO on the sintering temperature and the superconductivity for HgBa2Can-1CunO2(n+1)+d (Hg-12(n-1)n, n = 1, 2 and 3) were investigated. In the solid state reaction of HgO, BaO, CaO and CuO in the sealed quartz-tube, the upper sintering temperatures to obtain single-phase of Hg-12(n-1)n (n = 1, 2 and 3) increased with decreasing the carbon content in the BaO powder. According to our recent study, the carbon content was determined from the correlation with the lattice parameter. This suggests that an existence of carbon or carbonate impurity significantly influenced the phase formation. The optimal sintering temperatures starting from the BaO with almost minimized carbon content (approximately 0.15 mol%) were 800 °C, 725 °C and 775 °C, for the Hg-1201, -1212 and -1223, respectively. An increase in the sintering temperature led to the larger grain and better crystallinity, resulting in the excellent superconductivity. Improvements in superconducting volume-fraction, Tc and pinning properties were clearly observed in the Hg-1201 prepared from the high-purity BaO. This work indicates that the control of carbon content in the starting materials is one of the key factors to obtain high-quality Hg-based superconducting oxides.

Original languageEnglish
Pages (from-to)268-272
Number of pages5
JournalPhysica C: Superconductivity and its Applications
Volume335
Issue number1
DOIs
Publication statusPublished - 2000 Jun
Externally publishedYes

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purity
Carbon
carbon
sintering
Sintering
synthesis
Carbonates
Superconductivity
carbonates
superconductivity
Impurities
impurities
Temperature
Quartz
temperature
Solid state reactions
Powders
Oxides
Lattice constants
lattice parameters

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

Cite this

Synthesis of HgBa2Can-1CunO2(n+1)+d (n = 1,2,3) using high-purity BaO. / Yamamoto, Ayako; Hu, Wei Zhi; Tajima, Setsuko.

In: Physica C: Superconductivity and its Applications, Vol. 335, No. 1, 06.2000, p. 268-272.

Research output: Contribution to journalArticle

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