Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide–bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu’s parent body formed ~2 million years after the beginning of Solar System formation.

Functional materials such as magnetic, thermoelectric, and battery materials have been revolutionized through nanostructure engineering. However, spin caloritronics, an advancing field based on spintronics and thermoelectrics with fundamental physics studies, has focused only on uniform materials without complex microstructures. Here, we show how nanostructure engineering enables transforming simple magnetic alloys into spin-caloritronic materials displaying significantly large transverse thermoelectric conversion properties. The anomalous Nernst effect, a promising transverse thermoelectric phenomenon for energy harvesting and heat sensing, has been challenging to utilize due to the scarcity of materials with large anomalous Nernst coefficients. We demonstrate a remarkable ~ 70% improvement in the anomalous Nernst coefficients (reaching ~ 3.7 µVK⁻¹) and a significant ~ 200% enhancement in the power factor (reaching ~ 7.7 µWm⁻¹K⁻²) in flexible Fe-based amorphous materials by nanostructure engineering without changing their composition. This surpasses all reported amorphous alloys and is comparable to single crystals showing large anomalous Nernst effect. The enhancement is attributed to Cu nano-clustering, facilitating efficient transverse thermoelectric conversion. This discovery advances the materials science of spin caloritronics, opening new avenues for designing high-performance transverse thermoelectric devices for practical applications.

We propose a versatile method for measuring the thermophysical properties of composites by means of lock-in thermography (LIT) technique. The method is based on analyzing the thermal response distribution induced by periodic laser heating, which enables simultaneous high-spatial-resolution mapping of the effective out-of-plane thermal diffusivity, thermal conductivity, and volumetric heat capacity over the surface of the material. We validate the method using a reference material and demonstrate its capability in visualizing the effective properties of laminated carbon fiber reinforced plastic and carbon fiber reinforced thermoplastic with discontinuous fibers. The results showed that the LIT-based approach has high reproducibility and sensitivity, which allows observing the effect of fiber orientations on the effective properties. The proposed method will be useful for thermal research in composites, defect detection, and for investigating component geometric arrangement effects on the thermophysical properties.

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 SmCo₅/Bi_0.2Sb_1.8Te₃ multilayers exhibits an excellent transverse thermoelectric figure of merit z_xyT of 0.20 at room temperature owing to the optimized anisotropic structure and extremely low interfacial electrical and thermal resistivities between the SmCo₅ and Bi_0.2Sb_1.8Te₃ layers. The MCM-based thermopile module generates a maximum of 204 mW at a temperature difference of 152 K, whose power density normalized by the heat transfer area and temperature gradient is not only record-high among transverse thermoelectric modules but also comparable to those 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.