High-pressure synthesis of superconducting Nb1-xB2 (x = 0-0.48) with the maximum Tc = 9.2 K

Ayako Yamamoto, Chigaku Takao, Takahiko Masui, Mitsuru Izumi, Setsuko Tajima

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


Superconductivity with Tc above 9 K was found in metal-deficient NbB2 prepared under 5 GPa, while no clear superconductivity was observed down to 3 K in stoichiometric NbB2. The superconductivity was observed above x = 0.04 in Nb1-xB2, and the lattice parameters also changed abruptly at x = 0.04. As x increased, the transition temperature Tc slightly rose and fell with the maximum value of 9.2 K at x = 0.24 for the samples sintered at 5 GPa and 1200 °C. The Tc-value changed in the range from 7 to 9 K, depending on the sintering pressure. A series of Ta1-xB2 (0 ≤ x ≤ 0.24) was also synthesized under high pressure to examine a special effect of high-pressure synthesis.

Original languageEnglish
Pages (from-to)197-206
Number of pages10
JournalPhysica C: Superconductivity and its applications
Issue number3
Publication statusPublished - 2002 Dec 15
Externally publishedYes


  • High-pressure synthesis
  • NbB
  • Niobium diboride
  • Superconductivity
  • Tantalum diboride

ASJC Scopus subject areas

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


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