Quasiparticle entropy in the high-field superconducting phase of CeCoIn${}_5$

Abstract

The heavy-fermion superconductor CeCoIn${}_5$ displays an additional transition within its superconducting (SC) state, whose nature is characterized by high-precision studies of the isothermal field dependence of the entropy, derived from combined specific heat and magnetocaloric effect measurements at temperatures $T\ge 100$ mK and fields $H\le 12$ T aligned parallel, perpendicular and $18^{\circ }$ off the tetragonal [100] direction. For any of these conditions, we do not observe an additional entropy contribution upon tuning at constant temperature by magnetic field from the homogeneous SC into the presumed Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) SC state. By contrast, for $H\parallel [100]$ a negative isothermal entropy contribution, compatible with spin-density-wave (SDW) ordering, is found. Our data exclude the formation of a FFLO state in CeCoIn${}_5$ for out-of-plane field directions, where no SDW order exists.

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• Exploring the fragile antiferromagnetic superconducting phase in CeCoIn5
• Inherent spin density wave instability by vortices in superconductors with strong Pauli effects
• Field Evolution of the Fulde-Ferrell-Larkin-Ovchinnikov State in a Superconductor with Strong Pauli Effects

Cited by in corpus (9)

• Calorimetric Measurements of Magnetic-Field-Induced Inhomogeneous Superconductivity Above The Paramagnetic Limit
• Switching of magnetic domains reveals evidence for spatially inhomogeneous superconductivity
• From Kondo Lattices to Kondo Superlattices
• Zero-field Quantum Critical Point in CeCoIn${}_5$
• Observation of the in-plane magnetic field-induced phase transitions in FeSe
• Instability of Fulde-Ferrell-Larkin-Ovchinnikov states in three and two dimensions
• Microscopic Eilenberger theory of Fulde-Ferrell-Larkin-Ovchinnikov states in the presence of vortices
• Magnetic-field-induced 1st order transition to FFLO state at paramagnetic limit in 2D superconductors
• The Gor'kov and Melik-Barkhudarov correction to the mean-field critical field transition to Fulde-Ferrell-Larkin-Ovchinnikov states