Journal of Materiomics最新文献

SiGe based alloy is a promising medium-high temperature thermoelectric material that has been applied in the field of aerospace exploration. So far, utilizing the second phase to promote the scattering of phonons is a common way to improve the thermoelectric performance of SiGe based alloy, but this often deteriorates the electrical properties. In this study, the Si₈₀Ge₂₀P₁/CoSi₂ composites have been prepared by mechanical alloying and spark plasma sintering, and the content of cobalt silicide (CoSi₂) nanoparticles have been manipulated. Since the CoSi₂ nanoparticles possess higher carrier concentration and smaller work function than the Si₈₀Ge₂₀P₁ matrix, the carrier concentrations of composites have been pushed up due the charge transfer effect. Meanwhile, the formation of nano-sized phase interfaces and stacking faults in the composites has enhanced the scattering of low-frequency phonons. As a result, the optimal power factor of 3.41 mW⋅m⁻¹⋅K⁻² and thermal conductivity of 2.29 W⋅m⁻¹⋅K⁻¹ have been achieved, and the corresponding zT reaches up to 1.3 in the Si₈₀Ge₂₀P₁+0.5% CoSi₂ (in mole) composite at 873 K. This work provides a new idea for developing the performance of SiGe based alloy.

InTe single crystals have demonstrated great promise in the field of thermoelectric materials, particularly when oriented along the [110] direction. This specific crystal orientation exhibits higher electronic conductivity and lower thermal conductivity compared to other orientations of InTe. Through first-principles calculations, we identified the anisotropic valence band and phonon dispersion as the underlying factors. Moreover, reducing the density of In⁺ vacancies in InTe was found to lower the band effective mass and modulate carrier scattering, enhancing the material quality factor (B). To explore these findings, we systematically grew InTe single crystals, achieving exceptional thermoelectric performance. A record-breaking power factor of 12.0 μW·cm⁻¹·K⁻² and a dimensionless figure of merit (zT) of 0.5 at room temperature were obtained. Notably, InTe crystals oriented along [110] with low In⁺ vacancy density exhibited the highest average zT of 0.63 among InTe-based thermoelectric materials within the 300–473 K temperature range. Furthermore, we introduced an effective method of reducing In⁺ vacancies through Indium vapor annealing, resulting in the highest reported carrier mobility of 182 cm²·V⁻¹·s⁻¹ for InTe. Our study highlights the potential for improving InTe's thermoelectric performance near room temperature through vacancy modulation and crystal orientation.

BaTiO₃ (BTO) ferroelectric films, which are renowned for their lead-free compositions, superior stability, and absence of a wake-up effect, are promising candidate materials in the field of non-volatile memories. However, the prerequisites for high-temperature conditions in the fabrication of ferroelectric thin films impose constraints on the substrate choice, which has limited the advancement in non-volatile memories based on single-crystal flexible BTO films with robust ferroelectric properties. Herein, a technique has been developed for the fabrication of flexible devices using a pulsed laser deposition system. BTO ferroelectric films have then been deposited onto a flexible mica substrate, with SrTiO₃ (STO) serving as a buffer layer. The obtained flexible BTO devices exhibited excellent ferroelectricity, with a maximum polarization (2P_max) of up to 42.58 μC/cm² and a remnant polarization (2P_r) of up to 21.39 μC/cm². Furthermore, even after 1000 bending cycles, the bipolar switching endurance remained high at 10¹² cycles. After 10⁴ s, the flexible BTO device still maintained excellent polarization characteristics. These results make the flexible BTO ferroelectric thin film a potential candidate for the next generation of non-volatile memories.

Smart windows are an important strategy to reduce the energy consumption in buildings, which accounts for as much as 30%–40% of the society's energy consumption. VO₂-based thermochromic materials can intelligently regulate the solar heat gains of building interiors. However, the unmatched thermal emissivity (ɛ) modulation of traditional VO₂/glass systems, i.e., high emissivity at low temperatures and low emissivity at high temperatures, leads to additional heating and cooling energy loads in winter and summer, respectively. In this study, we propose a novel VO₂/polyacrylonitrile (PAN)/AgNW multilayer possessing flexible Ag nanowire supported Fabry–Pérot cavities, which synchronously achieves high modulation abilities in both solar spectrum (ΔT_sol of 13.6%) and middle infrared region (Δɛ of 0.50 at 8–13 μm). These achievements are the best among reports for pure VO₂ smart windows. This study provides a flexible and effective protocol to dynamically enhance the light and heat utilization for practical building windows.

AgNbO₃-based antiferroelectric ceramics can be used to prepare dielectric ceramic materials with energy storage performance. However, their efficiency is much lower than that of relaxors, which is one of the biggest obstacles for their applications. To overcome this problem, AgNbO₃ ceramics co-doped with Eu³⁺ and Ta⁵⁺ at the A- and B-sites were prepared in this work. The Ag_0.97Eu_0.01Nb_0.85Ta_0.15O₃ sample has a W_r of 6.9 J/cm³ and an η of 74.6%. The ultrahigh energy storage density and efficiency of Ag_0.97Eu_0.01Nb_0.85Ta_0.15O₃ has been ascribed to the synergistic effect of the increase in the breakdown electric field, the enhancement of antiferroelectric stability, the construction of multiphase coexistence, and the modification of the domain structure morphology. The Ag_0.97Eu_0.01Nb_0.85Ta_0.15O₃ ceramic is expected to be one of the options for preparing dielectric capacitors.

Motivated by advances in spintronic devices, extensive explorations are underway to uncover materials that host topologically protected spin textures, exemplified by skyrmions. One critical challenge involved in the potential application of skyrmions in van der Waals (vdW) materials is the attainment and manipulation of skyrmions at room temperature. In this study, we report the creation of an intrinsic skyrmion state in the van der Waals ferromagnet Fe₃GaTe₂. By employing variable temperature magnetic force microscopy, the skyrmion lattice can be locally manipulated on Fe₃GaTe₂ flakes. The ordering of skyrmion state is further analyzed. Our results suggest Fe₃GaTe₂ emerges as a highly promising contender for the realization of skyrmion-based layered spintronic memory devices.

Realizing robust magnetoelectric (ME) coupling effect near room temperature is still a long-standing challenge for the application of multiferroic materials in next-generation low-power spintronic and memory devices. Here we report a systematic study on the magnetic, dielectric, and ME coupling properties of Y-type hexaferrite Ba_0.5Sr_1.5Co₂Fe_12–xAl_xO₂₂ (x = 0.0, 0.5, 1.0) single crystals. The Al doping can induce the shifting of the alternating longitudinal conical (ALC)-proper screw (PS) magnetic phase transition temperature from 200 K for x = 0–365 K for x = 1.0. The most interesting feature is that the Ba_0.5Sr_1.5Co₂Fe₁₁AlO₂₂ single crystal displays a direct and converse ME coupling coefficient with ${\alpha }_H$ ∼3,100 ps/m and ${\alpha }_E$ ∼3,900 ps/m at 250 K, respectively, due to the Al-doped enhanced stability of ALC phase. Moreover, the exchange bias also verifies the strong coupling of electric and magnetic orders. These results provide a valuable insight on the modulation of ALC structure and the mechanism of ME effect in Y-type hexaferrites.

The interfacial incompatibility of the poly (ethylene oxide)-based electrolytes hinder the longevity and further practice of all-solid-state batteries. Herein, we present a productive additive 1-Fluoroadamantane facilitating to the distinct performance of the poly (ethylene oxide)-based electrolytes. Attributed to the strong molecular interaction, the coordination of the Li⁺-EO is reduced and the ‘bonding effect’ of anion is improved. Thus, the Li ⁺ conductivity is promoted and the electrochemical window is widened. The diamond building block C₁₀H₁₅⁻ strengthens the stability of the solid polymer electrolytes. Importantly, the 1-Fluoroadamantane mediates the generation of LiF in the interfaces, which fosters the interfacial stability, contributing to the long-term cycling. Hence, the symmetric cell (Li/Li) exhibits a long-term lithium plating/stripping for over 2,400 h. The 4.3 V LiNi_0.8Mn_0.1Co_0.1O₂/Li all-solid-state battery with the 1-Fluoroadamantane-poly (ethylene oxide) improved electrolyte delivers 600 times, with an impressive capacity retention of 84%. Also, the cell presents high capacity of 210 mA·h/g, and 170 mA·h/g at 0.1 C and 0.3 C respectively, rivalling the liquid electrolytes.

Recently, memristors have garnered widespread attention as neuromorphic devices that can simulate synaptic behavior, holding promise for future commercial applications in neuromorphic computing. In this paper, we present a memristor with an Au/Bi_3.2La_0.8Ti₃O₁₂ (BLTO)/ITO structure, demonstrating a switching ratio of nearly 10³ over a duration of 10⁴ s. It successfully simulates a range of synaptic behaviors, including long-term potentiation and depression, paired-pulse facilitation, spike-timing-dependent plasticity, spike-rate-dependent plasticity etc. Interestingly, we also employ it to simulate pain threshold, sensitization, and desensitization behaviors of pain-perceptual nociceptor (PPN). Lastly, by introducing memristor differential pairs (1T1R-1T1R), we train a neural network, effectively simplifying the learning process, reducing training time, and achieving a handwriting digit recognition accuracy of up to 97.19 %. Overall, the proposed device holds immense potential in the field of neuromorphic computing, offering possibilities for the next generation of high-performance neuromorphic computing chips.