# Magnetic proximity effect in [Nb/Gd] superlattices seen by neutron scattering

## TL;DR

This study uses neutron reflectometry to reveal how superconducting Nb layers influence the ferromagnetic Gd layers in superlattices, showing electromagnetic proximity effects suppress magnetic order below the superconducting transition.

## Contribution

It provides direct experimental evidence of electromagnetic proximity effects in S/F superlattices, highlighting the suppression of ferromagnetic order due to superconducting screening.

## Key findings

- Partial suppression of Gd ferromagnetism below superconducting transition
- Suppression amplitude decreases with increasing ferromagnetic layer thickness
- Electromagnetic effects dominate the magnetic response in the superlattices

## Abstract

We have used spin-polarized neutron reflectometry to investigate the magnetization profile of superlattices composed of ferromagnetic Gd and superconducting Nb layers. We have observed a partial suppression of ferromagnetic (F) order of Gd layers in [Gd($d_F$)/Nb(25nm)]$_{12}$ superlattices below the superconducting (S) transition of the Nb layers. The amplitude of the suppression decreases with increasing $d_F$. By analyzing the neutron spin asymmetry we conclude that the observed effect has an electromagnetic origin - the proximity-coupled S layers screen out the external magnetic field and thus suppress the F response of the Gd layers inside the structure. Our investigation demonstrates the considerable influence of electromagnetic effects on the magnetic properties of S/F systems.