Enhancement of Transverse Thermoelectric Conversion by Interface‐Induced Spin Current in Ferromagnetic Metal/Nonmagnetic Insulator Hybrid‐Structure

• Published in: Advanced functional materials 2024-12, Vol.34 (49), p.n/a
• Main Authors: Itoh, Takuma, Kozuka, Yusuke, Hirai, Takamasa, Uchida, Ken‐ichi
• Format: Article
• Language: English
• Subjects: anomalous Ettingshausen effect; Bismuth compounds; Charge materials; Energy harvesting; Ettingshausen effect; Ferromagnetic materials; Insulators; lock‐in thermography; Magnetic materials; Nernst-Ettingshausen effect; Rashba‐Edelstein effect; spin Peltier effect; Spintronics; Thermoelectric materials; Thermomagnetic effects; transverse thermoelectric conversion; Tungstates
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202409557

Transverse thermoelectric conversion phenomena including the anomalous Ettingshausen effect (AEE) and anomalous Nernst effect (ANE) in magnetic materials are actively investigated to realize versatile cooling and energy harvesting technologies. However, further improvement of the thermoelectric performance of AEE and ANE is still required, and most research efforts have focused on material exploration. Here, a new approach to improve the transverse thermoelectric conversion performance through interface engineering is reported by focusing on the transverse thermoelectric phenomena that output heat currents. A longitudinal charge current in a ferromagnetic metal Ni/nonmagnetic insulator Bi2WO6 hybrid‐structure induces a larger transverse heat current than that of AEE in a Ni single‐layer. It is indicated that the enhancement of the transverse thermoelectric conversion is due to the generation of a heat current concomitant with a spin current induced at the Ni/Bi2WO6 interface. This finding demonstrates that the interface of a magnetic metal/nonmagnetic insulator has a potential to improve the transverse thermoelectric performance, extending the applicability of nonmagnetic insulators to the field of spin caloritronics and thermoelectrics. This work demonstrates a new approach to improve transverse thermoelectric conversion, which is achieved simply by combining a nonmagnetic insulator with a ferromagnetic metal. This improvement is due to heat current generation concomitant with a spin current induced at the metal/insulator interface. This finding extends the applicability of nonmagnetic insulators to the field of spin caloritronics and thermoelectrics.