Anisotropic Superconductivity and Vortex Dynamics in Magnetically Coupled F/S and F/S/F Hybrids*

Magnetically coupled superconductor-ferromagnet hybrids offer advanced routes for nanoscale control of superconductivity. Magnetotransport characteristics and STM images of vortex structures in superconductor-ferromagnet hybrids reveal rich vortex phase diagram. We use a combination of STM and Ginzburg-Landau simulations to reveal that the magnetic stripe domain structure induces periodic local magnetic induction in the superconductor, creating a series of pinning-antipinning channels for externally added superconducting flux quanta. Such laterally confined Abrikosov vortices form quasi-1D arrays (chains). The transitions between multichain states occur through propagation of kinks at the intermediate fields. In F/S/F hybrids we demonstrate the evolution of the anisotropic conductivity in the superconductor that is coupled with two adjacent ferromagnetic layers. The anisotropic conductivity of up to three orders of magnitude can be achieved.