Giant electromagnetic proximity effect in superconductor/ferromagnet superlattices

TL;DR

This paper demonstrates a significantly enhanced electromagnetic proximity effect in superconductor/ferromagnet superlattices, revealing complex magnetic field behaviors influenced by layer orientation and magnetic ordering.

Contribution

It introduces the concept of a giant electromagnetic proximity effect in superlattices, extending understanding beyond simple S/F bilayers.

Findings

Magnetic field in superlattices is dramatically enhanced compared to bilayers.

The magnetic field decay depends on the orientation of layers and magnetic moments.

Results align with neutron scattering data in Nb/Gd superlattices.

Abstract

We show that in superlattices with alternating superconducting (S) and ferromagnetic (F) layers the spontaneous magnetic field induced in the superconducting layers due to the electromagnetic proximity effect becomes dramatically enhanced compared to the previously studied S/F bilayers. The effect reveals itself for the in-plane orientation of the magnetic moments both for ferromagnetic and anti-ferromagnetic ordering of the moments in the F layers. In the finite size samples the magnetic field decays from the sample surface towards the bulk of the structure, and the decay length strongly depends on the relative orientation of the sample surface, the layers planes and magnetic moments in the F layers. The obtained results provide additional insights into experimental data on the neutron scattering in Nb/Gd superlattices.