Nonuniform superconductivity and Josephson effect in conical ferromagnet

Abstract

Using the Gorkov equations, we provide an exact solution for a one-dimensional model of superconductivity in the presence of a conical helicoidal exchange field. Due to the special type of symmetry of the system, the superconducting transition always occurs into a nonuniform superconducting phase (in contrast with the Fulde-Ferrell-Larkin-Ovchinnikov state, which appears only at low temperatures). We directly demonstrate that the uniform superconducting state in our model carries a current and thus does not correspond to the ground state. We study in the framework of the Bogoliubov-de Gennes approach the properties of the Josephson junction with a conical ferromagnet as a weak link. In our numerical calculations, we do not use any approximations (such as, e.g., a quasiclassical approach), and we show a realization of an anomalous ${\varphi }_0$ junction (with a spontaneous phase difference ${\varphi }_0$ in the ground state). The spontaneous phase difference ${\varphi }_0$ strongly increases at high values of the exchange field near the borderline with a half-metal, and it exists also in the half-metal regime.

published version

References in corpus (7)

• Direct coupling between magnetism and superconducting current in Josephson Phi junction
• Anomalous Josephson Current in Junctions with Spin-Polarizing Quantum Point Contacts
• Magnetic moment manipulation by a Josephson current
• Signature of magnetic-dependent gapless odd frequency states at superconductor/ferromagnet interfaces
• Critical current of a Josephson junction containing a conical magnet
• Odd triplet superconductivity in a superconductor/ferromagnet structure with a spiral magnetic structure
• Generalized quasiclassical theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets

Cited by in corpus (1)

• Josephson current through a ferromagnetic bilayer: Beyond the quasiclassical approximation