Proximity-free enhancement of anomalous Nernst effects in metallic multilayers

TL;DR

This study demonstrates that the anomalous Nernst effect in metallic multilayers can be significantly enhanced through interface engineering, independent of magnetic proximity effects, indicating a new mechanism for thermoelectric conversion.

Contribution

It reveals a universal, proximity-free enhancement of the ANE in multilayers, highlighting the role of interfaces in thermoelectric phenomena in magnetic heterostructures.

Findings

ANE is enhanced with more interfaces in multilayers.

Enhancement occurs even without magnetic proximity effects.

Universal behavior observed across different metal combinations.

Abstract

The anomalous Nernst effect (ANE) has been investigated in alternately-stacked multilayer films comprising paramagnetic and ferromagnetic metals. We found that the ANE is enhanced with increasing the number of the paramagnet/ferromagnet interfaces with keeping the total thickness of the films constant, and that the enhancement appears even in the absence of magnetic proximity effects; similar behavior was observed not only in Pt/Fe multilayers but also in Au/Fe and Cu/Fe multilayers free from proximity ferromagnetism. This universal enhancement of the ANE in the metallic multilayers suggests the presence of unconventional interface-induced thermoelectric conversion in the Fe films attached to the paramagnets.