Anisotropic effect of Cd and Hg doping on Pauli limited superconductor CeCoIn${}_5$

Abstract

We investigated the effect of Cd and Hg doping on the first order superconducting (SC) transition and the high field-low temperature SC state of CeCoIn${}_5$ by measuring the specific heat of CeCo(In${}_{1-\mathrm{x}}$Cd${}_{\mathrm{x}}$)${}_5$ with x=0.0011, 0.0022 and 0.0033 and CeCo(In${}_{1-\mathrm{x}}$Hg${}_{\mathrm{x}}$)${}_5$ with x=0.00016, 0.00032, and 0.00048 at temperatures down to 0.1 K and fields up to 14 T. Cd substitution rapidly suppresses the cross-over temperature $T_0$, where the superconducting transition changes from second to first order, to $T$=0 K with x=0.0022 for $H\parallel$ [100], while it remains roughly constant up to x=0.0033 for $H\parallel$ [001]. The associated anomaly of the proposed FFLO state in Hg-doped samples is washed out by x=0.00048, while remaining at the same temperature, indicating high sensitivity of that state to impurities. We interpret these results as supporting the non-magnetic, possibly FFLO, origin of the high field - low temperature state in CeCoIn${}_5$.

References in corpus (3)

• Fulde-Ferrell-Larkin-Ovchinnikov State in Heavy Fermion Superconductors
• Reversible Tuning of the Heavy Fermion Ground State in CeCoIn${}_5$
• Pressure Study of Quantum Criticality in CeCoIn5

Cited by in corpus (7)

• Towards the identification of a quantum critical line in the (p, B) phase diagram of CeCoIn5
• Electronic tuning and uniform superconductivity in CeCoIn5
• Inherent spin density wave instability by vortices in superconductors with strong Pauli effects
• Behavior of the Quantum Critical Point and the Fermi-liquid Domain in the Heavy Fermion Superconductor CeCoIn5 studied by resistivity
• Pauli-limited upper critical field in dirty d-wave superconductors
• Possible Triplet Superconducting Order in Magnetic Superconducting Phase induced by Paramagnetic Pair-Breaking
• Superconductivity and non-Fermi-liquid behavior in the heavy-fermion compound CeCo${}_{1-x}$Ni${}_x$In${}_5$