Preparation and characterization of a new metal-intercalated graphite superconductor

Xiaofan Yang, Tomoya Taguchi, Yanan Wang, Tong He, Takaki Uchiyama, Akihisa Takai, Lei Zhi, Takafumi Miyazaki, Hidenori Goto, Ritsuko Eguchi, Hirofumi Ishii, Yen Fa Liao, Hitoshi Yamaoka, Yoshihiro Kubozono

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We produced a new superconducting binary elements intercalated graphite, CaxCs1-xCy, by the intercalation of Ca and Cs in highly-oriented pyrolytic graphite using the metal-alloy method. The superconducting CaxCs1-xCy sample was synthesized with the nominal x value of 0.8, i.e., Ca0.8Cs0.2Cy; its superconducting transition temperature, T c, was 7.4 K. Energy dispersive x-ray (EDX) spectroscopy provided the stoichiometry of Ca0.8(1)Cs0.2(1)Cy. The x-ray powder diffraction (XRD) pattern showed that Ca0.8(1)Cs0.2(1)Cy took on a CsC8-type hexagonal structure rather than a CaC6-type rhombohedral structure, suggesting that the chemical formula is 'Ca0.8(1)Cs0.2(1)C8'. The pressure dependence of T c for Ca0.8(1)Cs0.2(1)C8 was determined from the temperature dependence of its resistance under pressure, which exhibited a positive pressure dependence of T c below 9.3 GPa, and a rapid decrease above 9.3 GPa. We studied the pressure dependence of the crystal structure of Ca0.8(1)Cs0.2(1)C8, and the correlation between the T c and structure is fully discussed below.

Original languageEnglish
Article number016003
JournalMaterials Research Express
Issue number1
Publication statusPublished - Jan 2019


  • CsC structure
  • alloy method
  • binary elements intercalated graphite
  • pressure effect
  • superconductivity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Metals and Alloys


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