Phys.org March 30, 2021 An international team of researchers (USA – University of Wisconsin, University of Nebraska, Cornell University, Lawrence Berkeley National Laboratory, Argonne National Laboratory, South Korea, UK, Norway, Ireland) designed a new structure based on antiperovskites to manipulate the flow of spin information without moving the electrons’ charges through the material. Through X-ray diffraction they figured out at what point the structure of the material changed, indicating the emergence of the necessary arrangement of electronic spins. The material develops a magnetic order a little above room temperature. According to the researchers the ability to manipulate the arrangement of […]
Tag Archives: Advanced materials
Special heat treatment improves novel magnetic material
Science Daily March 31, 2021 Previously an international team of researchers (Germany, China) discovered that manganese silicide hosts magnetic skyrmions. Whereas Mn-Si alloy, B20 phase, is particularly suitable for the formation of skyrmion, MnSi1.7 is a contaminant. Now the team has developed a simple and efficient method to overcome this problem and prepare single‐phase MnSi films on Si substrates. It is based on the millisecond reaction between metallic Mn and Si using flash‐lamp annealing (FLA). By controlling the FLA energy density, single‐phase MnSi or MnSi1.7 or their mixture can be grown at will. Compared with bulk MnSi, the prepared MnSi […]
A material that is superconductive at room temperature and lower pressure
Phys.org March 22, 2021 Previously a team of researchers in the US (University of Rochester, SUNY Buffalo, University of Nevada) had shown that when a hydrogen-rich compound was squeezed to 267 GPa it became superconductive. In the new research the same team combined hydrogen with yttrium instead of carbon and sulfur greatly reducing the pressure. Two diamond anvils used to create the pressure were placed slightly apart with hydron gas and a sample of yttrium in its solid state between them. To prevent oxidation of the yttrium a sheet of palladium was placed between them. It also served as a […]
Scientists observe complex tunable magnetism in a topological material
Science Daily March 23, 2021 An international team of researchers (USA – Ames Laboratory, Iowa State University, University of Missouri Research Reactor, Oak Ridge National Laboratory, Harvard University, Canada) discovered that EuIn2As2 has collinear antiferromagnetic order where the magnetic moment direction determines either a topological-crystalline-insulator phase supporting axion electrodynamics or a higher-order-topological-insulator phase with chiral hinge states. They used neutron diffraction, symmetry analysis, and density functional theory results to demonstrate that EuIn2As2 exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180∘ rotation and time-reversal symmetries: C2×T=2′. Surfaces protected […]
Tunable smart materials
Science Daily March 22, 2021 Biological molecules in living organisms have a remarkable ability to form self-assembled structures when triggered by an external molecule. Based on this concept researchers in Japan created a tunable system involving poly(sodium acrylate) microparticles that can have one of two types of chemical groups attached. The adjustable parameters x and y refer to the molar percent of microparticles with β-cyclodextrin and adamantyl residues, respectively. The shape of assemblies formed by microparticles was dependent on the residue content. For assemblies to form, x needed to be at least 22.3. As the value of y increased, the […]
Wafer-thin nanopaper changes from firm to soft at the touch of a button
Science Daily March 24, 2021 Mimicking the sea cucumbers which adapt and strengthen their tissue so that their soft exterior immediately stiffens when attacked by predators, researchers in Germany have developed a mechanism to strengthen and stiffen a material using electric current. They developed cellulose nanofibrils/polymer nanopapers with tailor-made interactions by deposition of thin single-walled carbon nanotube electrode layers for Joule heating. Application of DC at specific voltages translates into significant electrothermal softening via dynamization and breakage of the thermo-reversible supramolecular bonds. The altered mechanical properties are reversibly switchable in power on/power off cycles. Currently a power source is needed […]
Controlled by light alone, new smart materials twist, bend and move
Science Daily March 12, 2021 The ability to topographically control photonic bandgaps allows programmable actuation of the elastomeric substrate in response to illumination. An international team of researchers (USA – Tufts University, Northwestern University, Italy) combined programmable photonic function with elastomeric material composites to generate optomechanical actuators that display controllable and tunable actuation as well as complex deformation in response to simple light illumination. They developed complex three-dimensional configurations, programmable motion patterns, and phototropic movement where the material moves in response to the motion of a light source. A “photonic sunflower” demonstrator device consisting of a light-tracking solar cell was […]
Jumping frost crystals: Lab works toward electrostatic de-icing
Phys.org February 24, 2021 Charge separation in frost has been studied in the past, but the effect has never been exploited to remove the frost from its surface. A team of researchers in the US (Virginia Tech, UC Santa Barbara) exploited the spontaneous electrification of ice to reveal a surprising phenomenon of jumping frost dendrites. They observed frost dendrites breaking off from mother dendrites and/or the substrate to jump out-of-plane toward an opposing polar liquid. They developed analytical and numerical models to estimate the attractive force between the frost dendrites and liquid and found it to be in good agreement […]
Molecular bridges power up printed electronics
Nanowerk February 25, 2021 Semiconducting transition metal dichalcogenides (TMDs) can be used to make conductive inks to manufacture printed electronic and optoelectronic devices. However, defects in their structure may hinder their performance. To boost the electrical performance of TMD based devices an international team of researchers (France, Ireland, UK) has developed ‘molecular bridges’- small molecules that interconnect the TMD flakes. The molecular bridges double up as walls, healing the chemical defects at the edges of the flakes and eliminating electrical vacancies that would otherwise promote energy loss and they provide researchers with a new tool to tailor the conductivity of […]
New phenomena for the design of future quantum devices
Nanowerk February 20, 2021 A team of researchers in the US (MIT, Pennsylvania State University, Argonne National Laboratory, Oak Ridge National Laboratory, NIST, University of Maryland) has shown that due to a new class of Kohn anomaly the topology of the electronic states in a topological material can leave fingerprints on their phonon properties. They experimentally observed it through inelastic x-ray and neutron scattering on WSM (Weyl semimetal) tantalum phosphide. Compared to the conventional Kohn anomaly, the Fermi surface in a WSM exhibits multiple topological singularities of Weyl nodes, leading to a distinct nesting condition with chiral selection, a power-law […]