Domain wall superconductivity in hybrid superconductor -- ferromagnetic structures

TL;DR

This paper uses the Ginzburg-Landau model to analyze how domain structures in ferromagnetic layers affect the nucleation and critical temperature of superconductivity in hybrid superconductor-ferromagnetic systems under external magnetic fields.

Contribution

It introduces a phenomenological approach to study the influence of domain walls and periodic domain structures on superconductivity nucleation and critical temperature behavior.

Findings

Superconductivity at domain walls is significantly affected by external magnetic fields.

Periodic domain structures cause overlapping of superconducting regions, altering critical field behavior.

The interplay between localized and delocalized superconductivity determines Tc dependence.

Abstract

On the basis of phenomenological Ginzburg-Landau approach we investigate the problem of order parameter nucleation in hybrid superconductor/ferromagnetic systems with a domain structure in applied external magnetic field. Both the isolated domain boundaries and periodic domain structures in ferromagnetic layers are considered. We study the interplay between the superconductivity localized at the domain walls and far from the walls and show that such interplay determines a peculiar field dependence of the critical temperature Tc. For a periodic domain structure the behavior of the upper critical field of superconductivity nucleation near Tc is strongly influenced by the overlapping of the superconducting nuclei localized over different domains.