Phys.org June 27, 2024 Recently a single-phase material concurrently exhibiting magnetism and the spin Hall effect has emerged as a scientifically and technologically interesting platform for realizing efficient and compact spin–orbit torque (SOT) systems. Researchers in South Korea demonstrated external-magnetic-field-free switching of perpendicular magnetization in a single-phase ferromagnetic and spin Hall oxide SrRuO3 by delicately altering the local lattices of the top and bottom surface layers of SrRuO3, while retaining a quasi-homogeneous, single-crystalline nature of the SrRuO3 bulk. This led to unbalanced spin Hall effects between the top and bottom layers. SrRuO3 exhibited the highest SOT efficiency and lowest power […]
Category Archives: Advanced materials
Researchers create new class of materials called ‘glassy gels’
Phys.org June 19, 2024 By swelling with solvent, glassy polymers can become gels that are soft and weak yet have enhanced extensibility. The marked changes in properties arise from the solvent increasing free volume between chains while weakening polymer–polymer interactions. A team of researchers in the US (North Carolina State University, University of Nebraska) developed a unique class of materials called glassy gels with desirable properties of both glasses and gels by solvating polar polymers with ionic liquids at appropriate concentrations. The ionic liquid increases free volume and extensibility despite the absence of conventional solvent. It forms strong and abundant […]
New fabric makes urban heat islands more bearable
Science Daily June 13, 2024 Urban areas have heat island effects that largely diminish the effectiveness of cooling textiles as wearable fabrics because they absorb emitted radiation from the ground and nearby buildings. A team of researchers in the US (University of Chicago, Duke University) developed a mid-infrared spectrally selective hierarchical fabric (SSHF) with emissivity greatly dominant in the atmospheric transmission window through molecular design, minimizing the net heat gain from the surroundings. The SSHF featured a high solar spectrum reflectivity of 0.97 owing to strong Mie scattering from the nano-micro hybrid fibrous structure. The SSHF was 2.3°C cooler than […]
This sound-suppressing silk can create quiet spaces
MIT News May 7, 2024 A team of researchers in the US (MIT, University of Wisconsin, Case Western Reserve University, Rhode Island School of Design) investigated traditional fabrics as emitters and suppressors of sound. When attached to a single strand of a piezoelectric fiber actuator, a silk fabric emitted up to 70 dB of sound. Despite the complex fabric structure, vibrometer measurements revealed behavior reminiscent of a classical thin plate. Fabric pore size relative to the viscous boundary layer thickness was found to influence acoustic-emission efficiency. They demonstrated two sound suppression using two distinct mechanisms. In the first, direct acoustic […]
New metasurface innovation unlocks precision control in wireless signals
Nanowerk April 22, 2023 Polarization conversion and beam scanning metasurfaces are commonly used to reduce polarization mismatch and direct electromagnetic waves in a specific direction to improve the strength of a wireless signal. However, identifying suitable active and mechanically reconfigurable metasurfaces for polarization conversion and beam scanning is a considerable challenge, and the reported metasurfaces have narrow scanning ranges, are expensive, and cannot be independently controlled. Researchers in South Korea proposed a reconfigurable transmissive metasurface combined with a scissor and rotation actuator for independently controlling beam scanning and polarization conversion functions. They constructed metasurface with rotatable unit cells (UCs) that […]
Researchers uncover kinky metal alloy that won’t crack at extreme temperatures at the atomic level
Phys.org April 22, 2024 Refractory alloys are very resistant to heat and wear but are not ductile or resistant to fracture. A team of researchers in the US (UC Berkeley, Lawrence Berkeley National Laboratory, UC Irvine, Pacific Northwest National Laboratory) examined the strength and fracture toughness of the Single-phase body-centered cubic (bcc) refractory alloy, NbTaTiHf, from 77 to 1473 kelvin. Whereas the glide and intersection of screw and mixed dislocations promoted strain hardening controlling uniform deformation, the coordinated slip of <111> edge dislocations with {110} and {112} glide planes prolonged nonuniform strain through formation of kink bands. These bands suppressed […]
New adhesive tape picks up and sticks down 2D materials as easily as child’s play
Science Daily February 9, 2024 The use of graphene and other 2D materials to create electronic and optoelectronic devices has been limited by the lack of effective large-area transfer processes. An international team of researchers (South Korea, Japan) has developed a method that uses functional tapes with adhesive forces controlled by ultraviolet light. The adhesion of the tape was optimized for the transfer of monolayer graphene, providing a yield of over 99%. Once detached from the growth substrate, the graphene/tape stack enables easy transfer of graphene to the desired target substrate. The method could be used to transfer other 2D […]
Newly developed material gulps down hydrogen, spits it out, protects fusion reactor walls
Phys.org December 14, 2023 An international team of researchers (USA, South Korea, France, Germany) investigated tantalum (Ta) coating deposited by cold spray technology on 316L stainless steel substrate as a potential plasma-facing material surface. High fluence low energy deuterium plasma irradiation experiments and subsequent thermal annealing cycles associated with thermal desorption spectrometry (TDS) demonstrated superior structural stability of the Ta coating. TDS experiments revealed the outgassing of deuterium (as measure of its retention) for cold spray Ta coatings to be three times higher than bulk Ta and two orders of magnitude greater than bulk polycrystalline W. X-ray photoelectron spectroscopy revealed […]
Novel liquid metal circuits for flexible, self-healing wearables
Nanowerk October 2, 2023 Present integrated stretchable electronics easily suffer from electrical deterioration and face challenges in forming robust multilayered soft-rigid hybrid configurations. Researchers in Singapore have developed a bilayer liquid-solid conductor (b-LSC) with amphiphilic properties that reliably interfaces with both rigid electronics and elastomeric substrates. The top liquid metal could self-solder its interface with rigid electronics at a resistance 30% lower than the traditional tin-soldered rigid interface. The bottom polar composite comprising liquid metal particles and polymers could not only reliably interface with elastomers but also help the b-LSC heal after breakage. The b-LSC fabrication could be scaled up […]
Researchers improve the performance of semiconductors using novel 2D metal
Phys.org August 18, 2023 Metal contacts to MoS2 field-effect transistors play a determinant role in the device electrical characteristics and need to be chosen carefully. However, they suffer from high contact resistance because of the Schottky barrier and the Fermi level pinning effects that occur at the contact/MoS2 interface. To overcome this issue an international team of researchers (the Netherlands, India) investigated 2D metallic TiSx (x ∼ 1.8) as top contacts for MoS2 FETs using atomic layer deposition for the synthesis of both the MoS2 channels as well as the TiSx contacts and assessed the electrical performance of the fabricated […]