Unconventional superconductivity in CeCoIn5 studied by the specific heat and magnetization measurements

Shugo Ikeda, Hiroaki Shishido, Miho Nakashima, Rikio Settai, Dai Aoki, Yoshinori Haga, Hisatomo Harima, Yuji Aoki, Takahiro Namiki, Hideyuki Sato, Yoshichika Onuki

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103 Citations (Scopus)


We measured the low-temperature specific heat in magnetic fields up to 80 kOe, together with the magnetization for the heavy-fermion superconductor CeCoIn5 with the transition temperature Tc = 2.25 K. CeCoIn5 is a strong-coupling superconductor with a large jump in the specific heat ΔC/Cn(Tc) = 4.7. The heavy-fermion state is significantly formed below 1 K, reaching at least 1070 mJ/K2·mol in magnetic fields. This large electronic specific heat coefficient at 0.25 K is, however, reduced with increasing magnetic field, ranging from 1070 mJ/K2·mol at 50 kOe to 820 mJ/K2·mol at 80 kOe. The upper critical field Hc2 at O K is estimated to be 116 kOe for H ∥ [100] and 49.5 kOe for H ∥ [001]. The present anisotropy of Hc2 is well explained by the anisotropic effective mass, but the magnitude of Hc2 is reduced strongly by the paramagnetic effect for both field directions.

Original languageEnglish
Pages (from-to)2248-2251
Number of pages4
JournalJournal of the Physical Society of Japan
Issue number8
Publication statusPublished - 2001 Aug


  • CeCoIn specific heat
  • Heavy fermion
  • Superconductivity


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