Thermoelectric generation based on spin Seebeck effects

TL;DR

This paper reviews the spin Seebeck effect (SSE) for thermoelectric generation, highlighting its unique features, theoretical efficiency limits, and recent device demonstrations, emphasizing its potential for flexible and scalable thermoelectric applications.

Contribution

It provides a comprehensive overview of SSE-based thermoelectric devices, including fundamental theory, efficiency analysis, and recent experimental progress, which is a novel synthesis in this field.

Findings

Fundamental characteristics of SSE devices are identified.

A theoretical efficiency limit for SSE thermoelectric conversion is established.

Preliminary device demonstrations show promising application potential.

Abstract

The spin Seebeck effect (SSE) refers to the generation of a spin current as a result of a temperature gradient in magnetic materials including insulators. The SSE is applicable to thermoelectric generation because the thermally generated spin current can be converted into a charge current via spin-orbit interaction in conductive materials adjacent to the magnets. The insulator-based SSE device exhibits unconventional characteristics potentially useful for thermoelectric applications, such as simple structure, device-design flexibility, and convenient scaling capability. In this article, we review recent studies on the SSE from the viewpoint of thermoelectric applications. Firstly, we introduce the thermoelectric generation process and measurement configuration of the SSE, followed by showing fundamental characteristics of the SSE device. Secondly, a theory of the thermoelectric conversion efficiency of the SSE device is presented, which clarifies the difference between the SSE and conventional thermoelectric effects and the efficiency limit of the SSE device. Finally, we show preliminary demonstrations of the SSE in various device structures for future thermoelectric applications and discuss prospects of the SSE-based thermoelectric technologies.