Multifunctional composite magnet realizing record-high transverse thermoelectric generation

Abstract

Permanent magnets are used in various products and essential for human society. If omnipresent permanent magnets could directly convert heat into electricity, they would lead to innovative energy harvesting and thermal management technologies. However, achieving such "multifunctionality" has been difficult due to poor thermoelectric performance of conventional magnets. In this work, we develop a multifunctional composite magnet (MCM) that enables giant transverse thermoelectric conversion while possessing permanent magnet features. MCM comprising alternately and obliquely stacked SmCo${}_5$/Bi${}_{0.2}$Sb${}_{1.8}$Te${}_3$ multilayers exhibits an excellent transverse thermoelectric performance at room temperature by optimizing its anisotropic structure. Owing to the extremely low interfacial electrical and thermal resistivities, the experimentally determined figure of merit $z_{\mathrm{xy}}T$ reaches 0.20 close to the analytically calculated ideal value. The MCM-based thermopile module generates 204 mW in maximum at a temperature difference of 152 K, whose power density normalized by heat transfer area and temperature gradient is not only record-high among transverse thermoelectric modules but also comparable to that of commercial thermoelectric modules utilizing the Seebeck effect. The multifunctionality of our MCM provides unprecedented opportunities for energy harvesting and thermal management everywhere permanent magnets are currently used.

19 pages, 10 figures, Figure 3 has been corrected

References in corpus (7)

• Zero-field Nernst effect in a ferromagnetic kagome-lattice Weyl-semimetal Co3Sn2S2
• Thermoelectrics: from Longitudinal to Transverse
• Observation of anomalous Ettingshausen effect and large transverse thermoelectric conductivity in permanent magnets
• Magnon-induced Giant Anomalous Nernst Effect in Single Crystal MnBi
• High-temperature dependence of anomalous Ettingshausen effect in SmCo${}_5$-type permanent magnets
• Hybridizing anomalous Nernst effect in artificially tilted multilayer based on magnetic topological material
• Permanent-magnet-based transverse thermoelectric generator with high fill factor driven by anomalous Nernst effect

Cited by in corpus (4)

• Fundamentals and advances in transverse thermoelectrics
• Simultaneous achievement of large anomalous Nernst effect and reduced thermal conductivity in sintered polycrystalline topological Heusler ferromagnets
• Quantitative measurements of transverse thermoelectric generation and cooling performances in SmCo${}_5$/Bi${}_{0.2}$Sb${}_{1.8}$Te${}_3$-based artificially tilted multilayer module
• Spin caloritronics: History and future prospects of experiments