TY - JOUR
T1 - Preparation and characterization of a new metal-intercalated graphite superconductor
AU - Yang, Xiaofan
AU - Taguchi, Tomoya
AU - Wang, Yanan
AU - He, Tong
AU - Uchiyama, Takaki
AU - Takai, Akihisa
AU - Zhi, Lei
AU - Miyazaki, Takafumi
AU - Goto, Hidenori
AU - Eguchi, Ritsuko
AU - Ishii, Hirofumi
AU - Liao, Yen Fa
AU - Yamaoka, Hitoshi
AU - Kubozono, Yoshihiro
N1 - Funding Information:
This study was partly supported by Grants-in-aid (26105004, 17K05500, 18K04940 and 18K18736) and by Program for Accelerating Brain Circulation from MEXT. This work was partly supported by JST ACT-C Grant Number JPMJCR12YW, Japan. The XRD measurements were performed under 2017B4132 and 2018A4133 of SPring-8.
Publisher Copyright:
© 2018 IOP Publishing Ltd.
PY - 2019/1
Y1 - 2019/1
N2 - 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.
AB - 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.
KW - CsC structure
KW - alloy method
KW - binary elements intercalated graphite
KW - pressure effect
KW - superconductivity
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U2 - 10.1088/2053-1591/aae9d2
DO - 10.1088/2053-1591/aae9d2
M3 - Article
AN - SCOPUS:85056123928
SN - 2053-1591
VL - 6
JO - Materials Research Express
JF - Materials Research Express
IS - 1
M1 - 016003
ER -