Magnetic field dependence of pairing interaction in ferromagnetic superconductors with triplet pairing

It is developed a microscopic description of superconductivity in ferromagnetic materials with triplet pairing triggered by the exchange of magnetic fluctuations. Instead widely used paramagnon model we work with phenomenological spectrum of fluctuations in the orthorhombic ferromagnet with strong magnetic anisotropy. Depending of the field orientation parallel or perpendicular to the direction of spontaneous magnetization the effective amplitude of pairing interaction proves to be decreasing or increasing function of magnetic field that allows to explain the drastic difference in magnitudes of upper critical field in these directions.Comment: 9 pages, no figure

Nonuniform states in noncentrosymmetric superconductors

In noncentrosymmetric crystals, nonuniform superconducting states are possible even in the absence of any external magnetic field. The origin of these states can be traced to the Lifshitz invariants in the free energy, which are linear in spatial gradients. We show how various types of the Lifshitz invariants in noncentrosymmetric superconductors can be derived from microscopic theory.Comment: 7 page

On the theory of polarized Fermi liquid

The transport equation for transverse vibrations of magnetization in spin polarized Fermi liquid is derived from integral equation for the vertex function. The dispersion law for the transverse spin waves is established. The existance of zero-temperature spin-waves attenuation is confirmed. The problem of similar derivation in ferromagnetic "Fermi liquid" is discussed.Comment: 3 pages, no figure

Superconductivity in Uranium Ferromagnets

The theoretical description and the survey of physical properties of superconducting states in the uranium ferromagnetic materials are presented. On the basis of microscopic theory is shown that the coupling between the electrons in these ferromagnetic metals by means of magnetization fluctuations gives rise the triplet pairing superconducting state and the general form of the order parameter dictated by the symmetry is established. The theory allows to explain some specific observations including peculiar phenomenon of reentrant superconductivity in URhGe in magnetic field perpendicular to the direction of spontaneous magnetization. In addition we describe several particular topics relating to uranium superconducting ferromagnets: (i) critical magnetic relaxation in dual localized-itinerant ferromagnets, (ii) phase transition to ferromagnetic state in Fermi liquid and UGe$_2$, (iii) superconducting ordering in ferromagnetic metals without inversion symmetry.Comment: 56 pages, 19 figure