Thermoelectric Generation Based on Spin Seebeck Effects

TLDR

The spin Seebeck effect generates a spin current from a temperature gradient in magnetic materials, and this spin current can be converted into a charge current via spin–orbit interaction, making insulator‑based SSE devices attractive for thermoelectric generation due to their simple structure, design flexibility, and scalable nature. This article reviews recent studies on the SSE from the perspective of thermoelectric applications. The review outlines the thermoelectric generation process and measurement configuration of the SSE, discusses its fundamental characteristics, presents a theory of its conversion efficiency that distinguishes it from conventional thermoelectric effects and defines its efficiency limit, and highlights preliminary demonstrations in various device structures. Preliminary demonstrations in diverse device structures suggest promising prospects for SSE‑based thermoelectric technologies.

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.