1. Preparation and characterization of a new metal-intercalated graphite superconductor
- Author
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Lei Zhi, Xiaofan Yang, Yoshihiro Kubozono, Ritsuko Eguchi, Yanan Wang, Takafumi Miyazaki, Takaki Uchiyama, Yen Fa Liao, Tong He, Hirofumi Ishii, Tomoya Taguchi, Hidenori Goto, Akihisa Takai, and Hitoshi Yamaoka
- Subjects
Superconductivity ,Materials science ,Polymers and Plastics ,Intercalation (chemistry) ,Metals and Alloys ,Analytical chemistry ,Crystal structure ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Pyrolytic carbon ,Graphite ,Spectroscopy ,Powder diffraction ,Stoichiometry - Abstract
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.
- Published
- 2018
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