Switching superconductivity in S/F bilayers by multiple-domain structures

TL;DR

This paper investigates how multiple magnetic domain structures in a superconductor/ferromagnet bilayer influence superconductivity, revealing that domain walls can enhance and control the critical temperature, enabling potential new device applications.

Contribution

It introduces a model of a ferromagnetic layer with rotating magnetic moments to study the impact of domain structures on superconductivity, highlighting a novel control mechanism.

Findings

Superconducting critical temperature is always enhanced by the domain structure.

The critical temperature exhibits reentrant behavior as a function of magnetic rotation wavelength.

Domain walls can be used to control superconductivity in bilayer devices.

Abstract

We consider the effect of a multiple magnetic domain structure in a superconductor/ferromagnet bilayer, modeled by a ferromagnetic layer with a rotating magnetic moment. The domain walls in this model are of equal size as the domains, and are of Neel type. We study the superconducting critical temperature as a function of the rotation wavelength of the magnetic moment. The critical temperature of the bilayer is found to be always enhanced by the domain structure, and exhibits an interesting reentrant behavior. We suggest that this effect can be used for a new device where superconductivity may be controlled by the domain structure of the magnetic layer.