Superconducting and Fermi Surface Properties of a Valence Fluctuation Compound CeIr2

• Published in: Journal of the Physical Society of Japan 2024-03, Vol.93 (3), p.1
• Main Authors: Omasa, Kazuyuki, Komoda, Takuya, Nakamura, Yusuke, Matsuoka, Eiichi, Kotegawa, Hisashi, Tou, Hideki, Sakurai, Takahiro, Ohta, Hitoshi, Nakamura, Ai, Homma, Yoshiya, Aoki, Dai, Satoh, Daisuke, Yoshida, Mitsuhiro, Mishra, Sanu, Sheikin, Ilya, Harima, Hisatomo, Sugawara, Hitoshi
• Format: Article
• Language: English
• Subjects: Coupling; Critical field (superconductivity); Debye temperature; Electrical resistivity; Fermi surfaces; Low temperature; Magnetic fields; Magnetic permeability; Magnetic properties; Plane waves; Superconductivity; Surface properties; Transition temperature
• ISSN: 0031-9015; 1347-4073
• DOI: 10.7566/JPSJ.93.034704

CeIr2 was reported as a valence fluctuation compound with a superconducting transition temperature of ∼0.3 K. To investigate its electronic and superconducting properties, we measured the electrical resistivity, magnetic susceptibility, and de Haas–van Alphen (dHvA) effect at low temperatures cooled to ∼30 mK and in high magnetic fields up to 36 T. The upper critical field (μ0Hc2 = 0.23 T) determined by the electrical resistivity under the magnetic field and the electron–phonon coupling constant (λep = 0.39) estimated from the Debye temperature suggested a weak-coupling BCS-type superconductivity. The dHvA effect measurements mapped the Fermi surface in detail. The dHvA branches with the frequencies of F = 122–2180 T and the effective masses of mc∗=0.83–2.4 m0 (m0: rest mass of an electron) were observed. These were reasonably explained by the band-structure calculation based on the full potential linearized augmented-plane-wave method within the local density approximation.