Interplay between Néel-type Skyrmions and Pearl Vortices in Thin Superconductor-Ferromagnet Heterostructures

TKM Institutsseminar


Elizaveta Andriyakhina


25/05/2023 12:30


10.01, Geb. 30.23, CS; and Zoom


University of Regensburg


Alexander Mirlin


In this study, we explore the complex interactions between superconductivity and magnetism in superconductor-ferromagnet heterostructures in the form of an interplay between Néel-type skyrmions and Pearl vortices in thin heterostructures. Our analysis of stray fields reveals how the presence of a vortex-antivortex pair influences the skyrmion radius and highlights the potential for the spontaneous generation of these pairs under certain conditions when a Néel-type skyrmion is present [1].
Furthermore, we investigate the repulsion between Néel-type skyrmions and Pearl vortices in chiral ferromagnetic films [2], finding that the repulsion is suppressed when the dimensionless strength of the vortex magnetic field increases. This results in intricate changes in the free energy and equilibrium distance between the skyrmion and vortex.
Finally, we develop a theory for the coaxial configuration of Néel-type skyrmions and Pearl vortices in thin superconductor-chiral ferromagnetic heterostructures [3]. By employing exact numerical solutions of the Euler-Lagrange equation and micromagnetic simulations, we show the significant impact of the Pearl vortex's inhomogeneous magnetic field on the skyrmion profile, including a dramatic increase in skyrmion radius and the inversion of its chirality. We introduce a novel two-parameter ansatz to represent the magnetization profile of the skyrmion in the presence of the vortex, demonstrating that both the material parameters of the heterostructure and the thickness of the superconductor control chirality inversion and radius expansion. Our findings offer valuable insights into Majorana modes localized at skyrmion-vortex pairs and carry implications for future research in superconductivity and magnetism.
[1] E.S. Andriyakhina, I.S. Burmistrov, "Interaction of a Neel-type skyrmion with a superconducting vortex", Phys. Rev. B 103, 174519 (2021) arxiv:2102.05434
[2] E.S. Andriyakhina, S. Apostoloff, I.S. Burmistrov, "Repulsion of a Néel-type skyrmion from a Pearl vortex in thin ferromagnet-superconductor heterostructures", Pis'ma v ZhETF, 116, 801 (2022) arxiv:2210.08790
[3] S.S. Apostoloff, E.S. Andriyakhina, P.A. Vorobyev, O.A. Tretiakov, I.S. Burmistrov, "Chirality inversion and radius blow-up of a Néel-type skyrmion by a Pearl vortex", arxiv:2212.08351