In a groundbreaking study, a team of researchers at NIMS has discovered that by stacking layers of thermoelectric and magnetic materials, a novel transverse thermoelectric effect can be generated. This effect allows for the conversion of energy between electric and heat currents that flow perpendicular to each other within the material. Unlike traditional thermoelectric devices that rely on the Seebeck effect, which produces a current parallel to the heat flow, this new mechanism offers a simpler structure with enhanced performance for energy harvesting and heat flux sensing applications.
While thermoelectric technologies based on the Seebeck effect have been extensively researched for their ability to convert waste heat into electricity, their complex structures often result in reduced efficiency and increased manufacturing costs. By utilizing transverse thermoelectric effects like the anomalous Nernst effect, researchers can simplify device designs and improve performance. However, the current room-temperature conversion efficiency of the anomalous Nernst effect is relatively low, limiting its practical applications.
To address this limitation, the NIMS team developed a thermoelectric composite structure consisting of a stack of thermoelectric silicon substrate and magnetic iron-gallium alloy thin film. By optimizing the thickness ratio between the two materials, the composite device was able to produce a transverse thermoelectric effect that was significantly larger than what could be achieved with the Fe-Ga alloy alone. This breakthrough marks the first experimental demonstration of its kind and opens up new possibilities for thermoelectric device development.
The composite device exhibited a maximum output voltage of 15.2 μV/K, which is approximately six times greater than the output generated by the Fe-Ga alloy based on the anomalous Nernst effect alone. This significant enhancement in performance showcases the potential of simple layered structures in improving thermoelectric conversion efficiency. The research team’s findings have implications for a wide range of practical applications in energy harvesting and heat flux sensing, with the potential to revolutionize the field of thermoelectric device technology.
Looking ahead, the researchers plan to further explore the use of large bulk materials to scale up the production of thermoelectric composites for practical applications. By expanding their research to include a wider range of materials and optimizing fabrication processes, the team aims to contribute to society’s energy conservation efforts through the development of more efficient thermoelectric power generation devices. This research represents a significant step forward in the field of thermoelectric materials and holds promise for addressing the growing demand for sustainable energy solutions in the future.