Experimental Observation of the Inverse Proximity Effect in Superconductor/Ferromagnet Layered Structures

TL;DR

This study provides experimental evidence of the inverse proximity effect, showing how ferromagnetism penetrates into a superconductor in layered structures, observed via NMR line shape changes in the superconducting state.

Contribution

First experimental observation of the inverse proximity effect in superconductor/ferromagnet heterostructures using NMR techniques.

Findings

NMR line shape changes in the superconducting state

Distortion of the high-field wing of the resonance line

Evidence of ferromagnetism penetration into the superconductor

Abstract

We have studied the nuclear magnetic resonance (NMR) of 51V nuclei in the superconductor/ferromagnet thin film heterostructures Ni/V/Ni and Pd{1-x}Fe{x}/V/Pd{1-x}Fe{x} in the normaland superconducting state. Whereas the position and shape of the NMR line in the normal state for the trilayers is identical to that observed in a single V-layer, in the superconducting state the line shape definitely changes, developing a systematic distortion of the high-field wing of the resonance line. We consider this as the first experimental evidence for the penetration of ferromagnetism into the superconducting layer, a phenomenon which has been theoretically predicted recently and dubbed the inverse proximity effect.