Browse Articles

Magnonic noise has unveiled magnon dynamics, including nonlinear scattering processes.

This study explores a novel approach to achieve field-free current-driven spin–orbit torque switching of perpendicular magnetization for MRAM applications. By adjusting growth protocols in Pt-based magnetic heterostructures, a previously overlooked laterally tilted texture and magnetic anisotropy are harnessed. These findings allow deterministic switching of perpendicular magnetization without an external magnetic field. Contrary to conventional assumptions, the observed nonlinear dependence on current density resembles a damping-like torque, challenging previous notions about its origin.

Schematic illustrations of the changes in the magnetic anisotropy by an applied electric field (E) in the strain directions are displayed. Under an applied E, the piezoelectric stress in the ferroelectric PMN-PT could be introduced in the tensile and compressive directions using positive and negative bias voltages, respectively, resulting in the changes in the magnetic anisotropy in the Co₂FeSi layer. The XMCD spectra of Fe and Co L-edges in Co₂FeSi under applying E showed the line shape changes only in the Fe site, which corresponds to the changes of orbital magnetic moment in Fe, while that in Co remains unchanged.

The fabrication and development of high-entropy alloys (HEAs) with exceptional functionalities is a rapidly expanding field. The extrinsic factors, such as the existence of grains and different phases, would complicate understanding the physical phenomena. We classified the epitaxial system into atomic-site disordered (ASD) and amorphous system into structurally disordered (SD) states, respectively, to exclude the extrinsic effects of HEAs. With a comprehensive study of the magnetic and transport properties, we can further promote the research of high entropy systems.

With the use of a fluorine-containing block providing a surface tension as low as that of PDMS (19.9 < \(\gamma\) < 21.5 mN/m), the PDMS-b-PPeFPA copolymer is synthesized to create a volume-symmetric lamellar structure. Under the symmetric confinement with simultaneous dual neutral interfaces, lamellar microdomains with a sub-10 nm half-pitch feature size are successfully oriented perpendicular to the interfaces at room temperature (RT). Together with unidirectionally aligned perpendicular lamellae along the electric vector in a short period (0.5 h) at RT, we demonstrate a unidirectional alignment of the perpendicular air–inorganic (oxidized PDMS) lamellae between the electrodes.

Oxide-based thermoelectric materials that exhibit a high figure of merit are promising because of their good chemical and thermal stabilities and their relative harmlessness compared with chalcogenide-based state-of-the-art thermoelectric materials. The layered barium-cobalt oxide (Ba_1/3CoO₂) exhibits a record-high ZT of 0.55 at 600 °C in air. The increase in ZT is directly originated by the decreased thermal conductivity of Ba_1/3CoO₂. As we hypothesized, the greater the atomic mass, the lower the thermal conductivity, resulting in higher ZT. The ZT is reliable and the highest among thermoelectric oxides. Moreover, this value is comparable to those of p-type PbTe and p-type SiGe.

Two-dimensional semiconductors are considered as field-effect transistors to overcome short channel effects and reduce the device size. As contacts to the metallic electrodes are decisive for the device performance, we study the electronic properties of contacts between Janus MoSSe and various two-dimensional metals. We demonstrate that weak interactions at these van der Waals contacts suppress Fermi level pinning and show that ohmic contacts can be formed for both terminations of Janus MoSSe, generating favorable transport characteristics.

A WO₃ nanoneedle film was developed for a gas sensor to detect low concentrations of acetone gas, which is a diabetes biomarker. The sensor exhibited a high response (19.72) to 10 ppmv acetone gas. The sensor also exhibited a high response (25.36) to 1 ppmv NO₂, which is related to asthma. The limits of detection for acetone and NO₂ gases were estimated to be 2.4 and 1.5 ppbv, respectively. The sensor exhibited superior ability to detect low concentrations of biomarker gases. The unique characteristics of the WO₃ nanoneedle film contributed to its high response rates.

Malaria continues to be among the most lethal infectious diseases. In the last two decades, we have witnessed unprecedented success in reducing the mortality rate. With the UN resolution of eradicating malaria by 2030 approaching fast, the scientific community has devoted substantial attention to interdisciplinary research using the latest opto-/magnetic-based technologies to detect a novel biomarker coming from the malarial pigment (hemozoin), which also carries vital information for discovering targeted drugs. This perspective article looks into the growing interest in this field and discusses the practical applicability of these sensing technologies.

This perspective highlights recent applications of ionogels that take advantage of their ionic conductivity, nonvolatility, and high thermal and electrochemical stability. Examples include sensors, batteries, electronics, 3D printing, and adhesives. Improving the mechanical properties of ionogels broadens the application space; thus, simple strategies to achieve tough ionogels are introduced. Finally, the potential applications and future opportunities of ionogels are discussed.

In this work, 3D printing shape of memory polymer (SMP) based smart structures is conducted using a Digital light processing 3D printer and a customized resin in combination with liquid crystals. Lattice structures are fabricated and programmed to achieve tunable mechanical properties. The strain-sensing response is measured to demonstrate the utility of these lattice structures as smart patches for joint movement sensing. Changes in the electrical resistance are measured during the stretching and compression of the structure. The SMPs can be prepared conveniently and can potentially be used for various applications, such as smart tools, toys, and meta-material sensors.

Osmotic energy generation, using aramid nanofiber (ANF) semiconductor membranes for light-driven proton transport, displayed wavelength and intensity-dependent potential and current under unilateral illumination. The simultaneous application of illumination and pressure led to a five-fold voltage increase and a three-fold current increase. Density functional theory calculations and spectroscopic measurements confirmed ANF’s role in photoinduced proton transport. This research has significant implications for developing flexible, stable ANF membrane-based energy devices.

Ba_0.95La_0.05SnO₃ epitaxial films grown on (0001)-oriented Al₂O₃ with a BaZrO₃/MgO template bilayer exhibit lower sheet resistance by three orders of magnitude compared with template-free films. These epitaxial films with single-crystalline level properties, including high ultraviolet‒visible transmittance (~82%) and high electromagnetic shielding effectiveness (~18.6 dB at 10 GHz), can be used for the development of stable and inexpensive optoelectronic and energy applications of epitaxial BLSO films grown on Al₂O₃.

Controlling molecular spin quantum bits optically could help us reduce decoherence and raise the working temperature of quantum computing. Here we show theoretically exchange interactions and spin dynamics could be mediated by optically driven triplet state, leading to quantum gate operations. This indicates a great potential for radical as molecular building block for quantum circuits. A molecular quantum architecture, combining molecular network and nano-photonics, was also proposed. We thus expect the computational exploration of chemical database for molecular quantum computing. This work would therefore open up a new direction to use optical instruments and ‘Click Chemistry’ towards molecular quantum technology.

Inspired by Bouligand structure in the dactyl club of the mantis shrimp, direct ink writing is used to 3D print Bouligand composites reinforced with glass microfibres at controllable pitch angles. The Bouligand composites with a pitch angle of 40˚ exhibited a maximum energy absorption of 2.4 kJ/m², which was 140 % higher than the unidirectional composites. The topography of the fractured surface supplemented with numerical simulations revealed the combination of crack twisting and crack bridging mechanisms. These findings have implications for the microstructural design of engineered composites using direct ink writing for applications in aerospace, transportation, defense, etc.

In this work, by involving high-energy scanning X-ray diffraction strain mapping, we identify and distinguish between structural and elastic heterogeneity in the extremely rejuvenated metallic glasses under triaxial compression. Microindentation hardness hints at an unsymmetrical hardening/softening picture and further reveals the complementary effects of stress and structure modulation. Our results suggest that simultaneous stress and structural modulation can be used to enhance rejuvenation beyond the limits known to date, and may therefore aid in the design of MGs with enhanced ductility and strain-hardening capability.

III-V commercial optical semiconductor GaP crystalizes in either zincblende or wurtzite structure at ambient pressure. Zincblende GaP transforms into orthorhombic phase across a critical pressure during compression, accompanying piezochromic transition, metallization and superconductivity. Upon decompression, superconductivity could be preserved toward ambient pressure and displays broadening features due to amorphization. It reveals the presence of two high-pressure superconducting phases.

A molecular imaging-based strategy was proposed for precise diagnosing the depression through specifically visualizing the inflammation status associated with depressed brain. The inflammation-targeting MRI nanoprobe that can specifically target the inflamed vascular endothelial cells was constructed through attaching the ICAM-1 targeting peptides on biocompatible Fe₃O₄ nanoparticle. Through nanoprobe-based SWI, the spatial distribution of inflammation in depressed brain can be mapped in vivo. This strategy not only facilitate insight into the biological mechanism underlying depression, but also provide a target within the depressed brain for the further development of anti-inflammatory therapies.

We present a strategy for significantly increasing the H contents on catalysts for the HER in alkaline electrolyte solutions, which were generated by combining ruthenium with H_xYO_2−x on an oxygen vacancy-rich graphene system. This strategy greatly increased the hydrogen coverage on the RuYO_2−x/C catalyst to enhance the HER performance.

The rise of three-dimensional topological insulators as an attractive playground for the observation and control of various spin-orbit effects has ushered in the field of topological spintronics. To fully exploit their potential as efficient spin-orbit torque generators, investigating the efficiency of spin injection and transport at various topological insulator/ferromagnet interfaces is crucial. Here, using all-optical time-resolved magneto-optical Kerr effect magnetometry, we demonstrate efficient room-temperature spin pumping in Sub/BiSbTe_1.5Se_1.5(BSTS)/Co₂₀Fe₆₀B₂₀(CoFeB)/SiO₂ thin films characterized by the spin-mixing conductances of the interface and the spin diffusion length in BSTS, and obtain an ultrahigh interfacial spin transparency.