Second anomaly in the specific heat of β-pyrochlore oxide superconductor KOs2O6

Zenji Hiroi, Shigeki Yonezawa, Jun Ichi Yamaura, Takaki Muramatsu, Yuji Muraoka

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61 Citations (Scopus)


Resistivity and specific heat have been measured on a single-crystalline sample of a β-pyrochlore oxide superconductor, KOs2O 6. It is found that a second peak in specific heat, which may evidence an unknown phase transition, appears at around Tp ∼ 7.5 K below the superconducting transition temperature Tc = 9.53 K. Applying magnetic fields up to 14 T, Tc is reduced gradually down to 7.1 K, while Tp is slightly raised and becomes even higher than Tc at 14 T, which implies that the second anomaly is not associated directly with the superconductivity. It is demonstrated, however, that there is significant communication between the two anomalies, suggesting that they come from the same electrons. It is also reported that the Sommerfeld coefficient γ in KOs2O6 is possibly much larger than those in other members of β-pyrochlore oxide superconductors, RbOs2O 6 (Tc = 6.3 K) and CsOs2O6 (T c = 3.3 K).

Original languageEnglish
Pages (from-to)1682-1685
Number of pages4
Journaljournal of the physical society of japan
Issue number6
Publication statusPublished - Jun 1 2005
Externally publishedYes


  • KOsO
  • Sommerfeld coefficient
  • Specific heat
  • Superconductivity
  • β-pyrochlore oxide

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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