Theory of Self-Induced Vortex State in Ferromagnetic Superconductors

Abstract

We have developed the quasi-classical formalism for a self-induced vortex state in ferromagnetic superconductors. By combining the spatially averaged approximation of the superconductivity with the phenomenological form of the ferromagnetism, we demonstrate the thermodynamic properties of the p-wave triplet equal-spin-pairing state with the spontaneous vortex lattice. The occurrence condition for the self-induced vortex state is discussed within this formalism. The comparison of the calculated quantities with the observed ones indicates that the self-induced vortex state indeed occurs in UCoGe, and its pairing symmetry seems to be the A2-type with a small spin difference in the gap magnitudes. In the vicinity of the ferromagnetic quantum critical point with a large uniform susceptibility, it is possible to exhibit the type-II to the type-I transition in the magnetization process.

8 pages, 8 figures

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Cited by in corpus (5)

• Review of U-based Ferromagnetic Superconductors: Comparison between UGe2, URhGe, and UCoGe
• Superconducting Gap of UCoGe probed by Thermal Transport
• Enhancement of superconductivity by pressure-induced critical ferromagnetic fluctuations in UCoGe
• Spin caloritronics as a probe of nonunitary superconductors
• Superconductivity at the Pressure-Induced Ferromagnetic Critical Region in UCoGe