Science and Technology of Advanced Materials最新文献

The magnetocaloric effect (MCE) provides a promising foundation for the development of solid-state refrigeration technologies that could replace conventional gas compression-based cooling systems. Current research efforts primarily focus on identifying cost-effective magnetic materials that exhibit large MCEs under low magnetic fields across broad temperature ranges, thereby enhancing cooling efficiency. However, practical implementation of magnetic refrigeration requires more than bulk materials; real-world devices demand efficient thermal management and compact, scalable architectures, often achieved through laminate designs or miniaturized geometries. Magnetocaloric materials with reduced dimensionality, such as ribbons, thin films, microwires, and nanostructures, offer distinct advantages, including improved heat exchange, mechanical flexibility, and integration potential. Despite these benefits, a comprehensive understanding of how size, geometry, interfacial effects, strain, and surface phenomena influence the MCE remains limited. This review aims to address these knowledge gaps and provide guidance for the rational design and engineering of magnetocaloric materials tailored for high-performance, energy-efficient magnetic refrigeration systems.

Heat flux sensors based on the anomalous Nernst effect (ANE) have emerged as a promising solution for achieving thin and flexible designs. ANE-based heat flux sensors typically employ thermopile structures composed of two ANE materials with opposite signs, connected in series to enhance sensing performance. However, a mismatch in the Seebeck coefficient between the two ANE materials causes a considerable offset voltage due to the Seebeck effect (SE) under oblique heat flux. This parasitic sensing voltage hinders direct sensing of heat flux in the intended direction. In this study, a sign-reversed ANE with matched Seebeck coefficient is examined in Fe₃Ln (Ln = Gd, Tb, Dy, Ho, and Er), enabling a thermopile structure free from the SE-induced offset voltage. Based on density functional theory calculations, Fe₃Ln is selected as a suitable candidate for exhibiting sign reversal of ANE while maintaining the Seebeck coefficient. At 300 K, Fe₃Ln (Ln = Gd, Tb, Dy, and Ho) exhibits a positive ANE sign, whereas Fe₃Er exhibits a negative ANE sign, facilitating the combination of two sign-reversed ANE materials. Among these, Fe₃Ho and Fe₃Er demonstrate the lowest Seebeck coefficient difference of 0.45 μV K^-1, minimizing the offset voltage-induced relative uncertainty, as confirmed by COMSOL simulations - comparable to that of other SE-based heat flux sensors. This study paves the way for the development of ANE-based heat flux sensors by introducing a novel approach to pairing opposite-ANE-sign materials with matched Seebeck coefficient, enabling direct and accurate heat flux sensing via thermopile structures.

This paper examines the phonon dispersion and static local atomic distortion of iron-manganese-based Elinvar alloys using high-resolution inelastic X-ray scattering, magnetization, neutron diffraction, and neutron total scattering. In this study, nonlinear phonon dispersion was observed for a transverse acoustic mode near zone center, associated with $(C_{11}-C_{12})/2$ elastic constants, over a wide temperature range along the $\Gamma \left(220\right)$ to X (310) points of the face-centered cubic system, indicating lattice instability coupled with tetragonal distortions in the long-wavelength limit. Bulk magnetization and neutron diffraction measurements suggest that the conventional ferromagnetic magnetostriction scenario is not the origin of Elinvar characteristics. Instead, the martensitic transformation and lattice instabilities underlie these phenomena. The reduced pair distribution function reveals a significant discrepancy between local and global (averaged) structures suggesting the influence of atomic-scale lattice disorder and instability in FeMn-based Elinvar alloys.

This study explores the synergistic potential of PEG-b-P(L-Arg)-based polyion complex micelles (Nano^ARGs) combined with an immune checkpoint inhibitor (PD-1 antibody) for cancer immunotherapy. Comprehensive experiments, including micelle preparation, in vivo anti-tumor activity evaluation, nitric oxide (NO) quantification, and immunofluorescence analysis, revealed significant insights. Nano^ARGs exhibited a biphasic effect on tumor growth: high doses inhibited tumor growth through NO generated from liberated Arg, whereas low doses promoted tumor progression. The combination treatment demonstrated significant synergistic anti-tumor activity without notable adverse effects, and treated mice tolerated the regimen well. This approach elevated NO levels in serum and tumor tissues, enhanced immune cell infiltration into tumor tissues, and facilitated the polarization of tumor-associated macrophages to the M1 phenotype. PD-1 antibody further amplified these effects by blocking PD-1/PD-L1 interactions and reactivating T cells. These results underscore the therapeutic potential of this novel approach, providing a foundation for optimizing tumor immunotherapy strategies and advancing clinical applications. Future research will focus on elucidating the mechanisms of action and expanding the scope of this promising treatment.

The transverse thermoelectric generation and cooling performances in a thermopile module composed of recently developed SmCo₅/Bi_0.2Sb_1.8Te₃ artificially tilted multilayers are evaluated quantitatively. When a large temperature difference of 405°C is applied to the SmCo₅/Bi_0.2Sb_1.8Te₃-based module, the open-circuit voltage and output power reach 0.51 V and 0.80 W, respectively. The corresponding maximum power density is 0.16 W/cm², even if the power is normalized by the device area including areas that do not contribute to the power generation, such as epoxy resin, electrodes, and insulating layers. The maximum energy conversion efficiency for our module in this condition is experimentally determined to be 0.92%. Under the cooling operation, the same module exhibits the maximum temperature difference of 9.0°C and heat flow at the cold side of 1.6 W. Although these values are lower than the ideal thermoelectric performance expected from the material parameters due to the imperfections associated with modularization, the systematic investigations reported here clarify a potential of the SmCo₅/Bi_0.2Sb_1.8Te₃ artificially tilted multilayers as thermoelectric generators and cooling devices.

Current tumor therapies face significant limitations such as hypoxic microenvironments, systemic toxicity, and immunosuppression. Thylakoid-based nanomaterials strategically integrate the structural-functional properties of natural biological components with the versatility of nanotechnology. These biomaterials have garnered substantial scientific interest due to their promising therapeutic potential in oncology. Thylakoids perform essential biological functions including solar energy absorption, photolytic oxygen generation, and operation of photosynthetic electron transport chains. Harnessing thylakoid-specific photochemical properties through nanoscale hybridization offers an innovative paradigm for developing multifunctional platforms in oncotherapy. This review summarizes current challenges in tumor therapy and the advantages of thylakoid-based nanomaterials in addressing these limitations. We further examine recent advances in the engineering design of thylakoid-based nanomaterials and their therapeutic applications. Finally, we discuss existing challenges and future prospects in this field.

Magnetic thin films and nanostructures present a unique challenge for a range of thermal measurements, with important consequences for both fundamental physics and material science and applications. This paper reviews the unique capabilities for measurement and control of these systems using thermal gradients applied using micro- and nanofabricated silicon-nitride membrane platforms. Supporting a thin film or nanostructure removes bulk heat sinks from the tiny structure, enabling otherwise challenging or impossible measurements including thermal conductivity, Seebeck coefficient, Peltier coefficient, magnon drag, both the anomalous and planar Nernst effect, specific heat, and novel manifestations of thermally assisted spin transport. After providing some historical context and motivation and overviewing the design and fabrication of silicon-nitride membrane thermal platforms, example data for each of the measurements above is reviewed, and the paper concludes with a consideration of the outlook for measurements enabled by these techniques.

We report on various magnetic configurations including spirals and skyrmions at the surface of the magnetic insulator Cu ${ }_2$ OSeO ${ }_3$ at low temperatures with a magnetic field applied along 100 using resonant elastic X-ray scattering (REXS). We observe a well-ordered surface state referred to as a distorted tilted conical spiral (dTC) phase over a wide range of magnetic fields. The dTC phase shows characteristic higher harmonic magnetic satellites in the REXS reciprocal space maps. Skyrmions emerge following static magnetic field cycling and appear to coexist with the dTC phase. Our results indicate that this phase represents a distinct and stable surface state that does not disappear with field cycling and persists until the field strength is increased sufficiently to create the field-polarized state.

The anatase form of TiO₂ is a widely studied material due to its broad range of applications. Epitaxial anatase thin films have attracted significant attention because of their enhanced electrical and optical properties. However, fabricating anatase thin films remains challenging due to their metastability and the need for highly sophisticated fabrication techniques. On-site controlled hydrolysis is a simple, cost-effective, and rapid method for producing smooth, compact thin films on various surfaces. In this study, we demonstrate a straightforward approach to fabricating highly oriented epitaxial anatase thin films on LaAlO₃ substrates using different solvent mixtures. The epitaxial orientation and film quality were analyzed using X-ray diffraction pole figures and rocking curves, while surface morphology was characterized by Scanning electron microscopy and atomic force microscopy. Our results indicate that thin film quality and morphology are primarily influenced by the annealing temperature rather than the choice of solvent or titanium precursor, confirming the feasibility of a scalable, low-cost epitaxial fabrication technique for anatase thin films.