Magnetic-domain-controlled vortex pinning in a superconductor/ferromagnet bilayer

TL;DR

This study demonstrates how magnetic domain patterns in a ferromagnetic layer can be used to control vortex pinning in an overlying superconductor, with bubble domains providing the most effective pinning.

Contribution

It introduces a method to tune vortex pinning in superconductor/ferromagnet bilayers by manipulating magnetic domain configurations, especially bubble domains.

Findings

Bubble domains provide the strongest vortex pinning.

Pinning effectiveness can be controlled by adjusting bubble size, density, and magnetization.

Magnetic domain patterns significantly influence vortex behavior in the superconductor.

Abstract

Vortex pinning in a type-II superconducting Pb film covering a Co/Pt multilayer with perpendicular magnetic anisotropy is investigated. Different stable magnetic domain patterns like band and bubble domains can be created in the Co/Pt multilayer, clearly influencing the vortex pinning in the superconducting Pb layer. Most effective pinning is observed for the bubble domain state. We demonstrate that the pinning properties of the superconductor/ferromagnet bilayer can be controlled by tuning the size, density and magnetization direction of the bubbles.