Magnetic structures in the coexistence phase of superconductivity and weak ferromagnetism

Domain Meissner state and spontaneous vortex-antivortex generation in the ferromagnetic superconductor EuFe 2 (As 0.79 P 0.21 ) 2

“…However, a conventional vortex phase is impossible because, in the absence of the external magnetic field, the global magnetization is zero. Rather, the first-order transition into a spontaneous V-AV state was predicted ( 19 , 21 ), when the FM domains carry vortex lattices of opposite polarities. In the limit of a dense vortex lattice, the energy E DVS of this new DVS differs from E FM only by the vortex lattice energy: E DVS ≃ E FM + M H c1 d F (see Fig.…”

Size of stripe domains in a superconducting ferromagnet

“…We have shown that the ratio l S /L z follows a universal dependence on the normalized penetration depth λ/L z and the normalized effective wall thicknessw/L z (see Figs. [4][5][6]. In addition to the exact numerical dependence, we have derived analytical expressions of this relation in limit cases.…”

“…In the discovered Uranium-based superconducting ferromagnets (SFM) UGe 2 1 , URhGe 2 and UCoGe 3 the Curie temperature Θ is much higher than the superconducting critical temperature T c which means that superconductivity appears in the ferromagnetic state where it is usually a domain structure (DS) which develops. In previous works [4][5][6][7][8] the influence of the superconducting screening currents on the DS has been studied in the case of thick or bulk systems, when the thickness 2L z along the easy magnetization direction is much larger than both the transverse domain width l (see Fig. 1) and the London penetration depth λ.…”

Phase transitions in the domain structure of ferromagnetic superconductors

“…The interaction between magnetic induction and superconductivity may strongly influence the properties of the domain structure and can even cause an intrinsic domain structure generation which was first addressed by Krey [8]. In the limit T c < θ the domain wall energy is too large and this prevents the formation of the intrinsic domain structure [9]. However, due to the demagnetization effect the domains structure is inherent to the majority of the ferromagnetic films.…”