Zero-magnetic-field operation of ordinary-Nernst-effect-based transverse thermoelectric module using embedded permanent magnets

The ordinary Nernst effect enables large transverse thermoelectric conversion in semimetals, but its operation requires the application of an external magnetic field. In this study, we propose a transverse thermoelectric conversion module structure with embedded permanent magnets and demonstrate thermoelectric power generation by the ordinary Nernst effect in the absence of an external magnetic field. In our prototype module comprising alternately stacked Bi₈₈Sb₁₂ slabs and Nd₂Fe₁₄B-type permanent magnets, the stray magnetic field generated by the remanent magnetization of the Nd₂Fe₁₄B-type magnets is always applied to the Bi₈₈Sb₁₂ slabs, and a power of 13.2 μW is generated due to the ordinary Nernst effect at a temperature difference of 120 K and average temperature of 260 K at zero external field. This thermoelectric module concept will contribute to the further development of transverse thermoelectric conversion technologies utilizing permanent magnets.