Thermoelectric Signal Enhancement by Reconciling the Spin Seebeck and Anomalous Nernst Effects in Ferromagnet/Non-magnet Multilayers

TL;DR

This study demonstrates that selecting appropriate non-magnetic materials and increasing multilayer layers in ferromagnet/non-magnet structures enhances thermoelectric signals by reconciling spin Seebeck and anomalous Nernst effects, advancing magnetic thermoelectric device development.

Contribution

It introduces a method to improve thermoelectric signals in FM/NM heterostructures by optimizing NM material properties and multilayer configurations, combining spin Seebeck and anomalous Nernst effects.

Findings

Thermoelectric signal is enhanced by matching NM spin Hall angle to ANE sign.

Increasing multilayer layers enlarges thermoelectric voltage and reduces device resistance.

Experimental results suggest potential for magnetic-based thermoelectric devices.

Abstract

The utilization of ferromagnetic (FM) materials in thermoelectric devices allows one to have a simpler structure and/or independent control of electric and thermal conductivities, which may further remove obstacles for this technology to be realized. The thermoelectricity in FM/non-magnet (NM) heterostructures using an optical heating source is studied as a function of NM materials and a number of multilayers. It is observed that the overall thermoelectric signal in those structures which is contributed by spin Seebeck effect and anomalous Nernst effect (ANE) is enhanced by a proper selection of NM materials with a spin Hall angle that matches to the sign of the ANE. Moreover, by an increase of the number of multilayer, the thermoelectric voltage is enlarged further and the device resistance is reduced, simultaneously. The experimental observation of the improvement of thermoelectric properties may pave the way for the realization of magnetic-(or spin-) based thermoelectric devices.