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Full-Heusler alloys with earth-abundant elements exhibit high mechanical strength and favorable electrical transport behavior, but their high intrinsic lattice thermal conductivity limits potential thermoelectric application. Here, the thermoelectric transport properties of Fe-based Full-Heusler Fe2MAl (M = V, Nb, Ta) alloys are comprehensively investigated utilizing density functional theory. The results suggest that Fe2NbAl exhibits exceptionally low lattice thermal conductivity due to low phonon velocities and weakly bound Nb atoms. In Fe2NbAl, the underbonding of the Nb atoms leads large Grüneisen parameters and high anharmonic scattering rates of low-frequency acoustic phonon. Meanwhile, the high band degeneracy and large electrical conductivity lead to a maximum p-type power factor of 255.6 μW·K−2·cm−1 at 900 K. The combination of low lattice thermal conductivity and favorable electrical transport properties leads a maximum p-type dimensionless figure of merit of 1.7. Our work indicates Fe2NbAl, as a low-cost, environmentally friendly, is a potential high-performance p-type thermoelectric material. [ABSTRACT FROM AUTHOR]

Thermo‐electro‐magnetic materials with simultaneously large magnetocaloric (MC) and thermoelectric (TE) effects are the core part for designing TE/MC all‐solid‐state cooling devices. Compositing MC phase with TE material is an effective approach. However, the elemental diffusion and chemical reaction occurring at the two‐phase interfaces could significantly impair the cooling performance. Herein, Gd/Bi0.5Sb1.5Te3 (Gd/BST) composites were prepared by a low‐temperature high‐pressure spark plasma sintering method with an aim to control the extent of interfacial reaction. The reaction of Gd with the diffusive Te and the formation of GdTe nanocrystals were identified at the Gd/BST interfaces by the atomic‐resolution microscope. The formed BiTe' antisite defects and enhanced {000 l} preferential orientation in BST are responsible for the increased carrier concentration and mobility, which leads to optimized electrical properties. The heterogeneous interface phases, along with antisite defects, favor the phonon scattering enhancement and lattice thermal conductivity suppression. The optimized composite sintered at 693 K exhibited a maximum ZT of 1.27 at 300 K. Furthermore, the well‐controlled interfacial reaction has a slight impact on the magnetic properties of Gd and a high magnetic entropy change is retained in the composites. This work provides a universal approach to fabricating thermo‐electro‐magnetic materials with excellent MC and TE properties. [ABSTRACT FROM AUTHOR]

Nanostructured transition metal dichalcogenide MnSe2 has attracted much attention due to its fascinating magnetic properties. In this article, a series of MnSe2 nanoparticles with different particle sizes are successfully prepared by a facile top‐down method of solid‐state reaction combined with ball milling, and the effects of ball milling on the phase composition, microstructure and magnetic properties of the MnSe2 are systematically studied. The results show that pure MnSe2 microparticles are obtained by the solid‐state reaction, however, partial MnSe2 is decomposed after ball milling for 16 h. The average particle size of the MnSe2 gradually decreases with the increase of milling time. MnSe2 nanoparticles with average particle size approximately 65 nm are obtained after milling for 40 h. After milling, the antiferromagnetic MnSe2 nanoparticles exhibit weak ferromagnetic characteristics due to the surface effect and the microstrain induced by ball milling. The residual magnetization (Mr) and coercivity (Hc) of the sample gradually increase as the particle size decreases. The Mr and Hc of the sample milled for 40 h reach 70.13 × 10−4 emu g−1 and 67.47 Oe, respectively. [ABSTRACT FROM AUTHOR]

Currently, the most promising breakthrough to the main bottleneck of in-plane heat dissipation technology based on the Peltier effect is the development of high-performance thermoelectric (TE) films. Herein, a series of p-type Bi0.5Sb1.5Te3 (BST)/xFe-BST epoxy multilayer films (Fe nanoparticles (Fe-NPs)-BST (Fe-BST) layer x = 0, 1, 2, 3 and 4) were designed and prepared by inserting a magnetic layer into two TE layers. The metallic magnetic Fe-NP layers as electron carrier expressways were introduced into BST epoxy multilayer films to produce a high-speed conductive channel and extra interlayer magnetic scattering to improve the electrical transport performance of the BST epoxy multilayer films. The electrical conductivity of the BST/xFe-BST epoxy multilayer films is significantly increased due to a surge in carrier mobility. Magnetoresistance shows that the Fe-NP layer in BST/xFe-BST epoxy multilayer films is able to produce extra interlayer magnetic scattering (spin-dependent scattering and weak-localization pinning), suppressing the decrease of the Seebeck coefficient. As a result, the maximum power factor (2.29 × 10−3 W K−2 m−1) of BST/Fe-BST epoxy multilayer films increased by 139% compared to that of the BST epoxy multilayer film, and the maximum cooling temperature difference was enhanced by 1.2 times. The interlayer coupling between magnetic/TE layers is utilized to introduce a new effect of thermo-electro-magnetic coupling in this study, which endowed the thermoelectromagnetic films with certain magnetic properties and significantly enhanced TE conversion performance, providing a new way for the preparation of high-performance TE films. [ABSTRACT FROM AUTHOR]