Competition between BCS superconductivity and ferromagnetic spin fluctuations in MgCNi3

L. Shan; Z. Y. Liu; Z. A. Ren; G. C. Che; H. H. Wen

doi:10.1103/PhysRevB.71.144516

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Competition between BCS superconductivity and ferromagnetic spin fluctuations in MgCNi3

L. Shan, Z. Y. Liu, Z. A. Ren, G. C. Che, H. H. Wen

DOI 10.1103/PhysRevB.71.144516 · Physical Review B

T1

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Abstract

The low temperature specific heat of the superconductor MgCNi3 and a nonsuperconductor MgC0.85Ni3 is investigated in detail. An additional contribution is observed from the data of MgCNi3 but absent in MgC0.85Ni3, which is demonstrated to be insensitive to the applied magnetic field even up to 12T. A detailed discussion on its origin is then presented. By subtracting this additional contribution, the zero field specific heat of MgCNi3 can be well described by the BCS theory with the gap ratio (Δ∕kBTc) determined by the previous tunneling measurements. The conventional s-wave pairing state is further proved by the magnetic field dependence of the specific heat at low temperatures and the behavior of the upper critical field.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
MgCNi3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	6.7	Pressure not reported	unknown