Phys.org June 7, 2024 Iron-based high-temperature (high-Tc) superconductors have good potential to serve as materials in next-generation superstrength quasipermanent magnets owing to their distinctive topological and superconducting properties. However, their unconventional high-Tc superconductivity paradoxically associates with anisotropic pairing and short coherence lengths, causing challenges by inhibiting supercurrent transport at grain boundaries in polycrystalline materials. An international team of researchers (Japan, UK) manipulated intricate polycrystalline microstructures resulting in a bulk Ba0.6K0.4Fe2As2 permanent magnet with a magnetic field that was 2.7 times stronger than previously reported. They demonstrated magnetic field stability for a practical 1.5 T permanent magnet, which is a vital aspect […]
Tag Archives: Materials science
Electrified charcoal ‘sponge’ can soak up CO2 directly from the air
Science Daily June 5, 2024 An international team of researchers (UK, Hong Kong, USA – Cornell University, Italy) introduced a new class of designer sorbent materials known as ‘charged-sorbents’. The materials were prepared through a battery-like charging process that accumulates ions in the pores of low-cost activated carbons, with the inserted ions then serving as sites for carbon dioxide adsorption. The charging process accumulated reactive hydroxide ions in the pores of a carbon electrode, and the resulting sorbent material could rapidly capture carbon dioxide from ambient air by means of (bi)carbonate formation. Unlike traditional bulk carbonates, charged-sorbent regeneration could be […]
New metal-free porous framework materials may have potential for hydrogen storage
Phys.org May 22, 2024 The isoreticular principle, which allows families of structurally analogous frameworks to be built in a predictable strategies do not translate to other common crystalline solids, such as organic salts, in which the intermolecular ionic bonding is less directional. Researchers in the UK showed that chemical knowledge could be combined with computational crystal-structure prediction (CSP) to design porous organic ammonium halide salts that contain no metals. The nodes in the salt frameworks were tightly packed ionic clusters that directed the materials to crystallize in specific ways on the predicted lattice energy landscapes. The energy landscapes allowed them […]
Researchers create new type of composite material for shielding against neutron and gamma radiation
Phys.org May 24, 2024 Researchers in China created a new type of composite material for shielding against neutron and gamma radiation using micron plate Sm2O3 (samarium oxide) to reinforce boron-containing polyethylene with different specific surface areas and particle size distributions. The fillers were added to boron-containing polyethylene to create composites. The composites showed improved thermal stability, increased the melting temperature, mechanical strength, and radiation shielding properties compared to materials without the fillers. Tests revealed that the composite material could block 98.7% of neutron radiation from a 252Cf source and 72.1% of gamma radiation from a 137Cs source when the material […]
Metalens expands Its reach from light to sound
Science Daily May 14, 2024 An important hurdle for using metalenses for manipulating waves is due to the severe hampering of the angular response originating from coma and field curvature aberrations, which result in a loss of focusing ability. Researchers in South Korea developed a blueprint by introducing the notion of a wide field-of-hearing (FOH) metalens, designed particularly for capturing and focusing sound with decreased aberrations. Employing an aberration-free planar-thin metalens that leverages perfect acoustic symmetry conversion, they experimentally realized a robust wide FOH capability of approximately 140 deg. in angular range. The metalens featured a relatively short focal length, […]
Researchers make a surprising discovery: Magnetism in a common material for microelectronics
Phys.org May 15, 2024 Nickel monosilicide (NiSi) is widely used to connect transistors in semiconductor circuits. Earlier theoretical calculations had incorrectly predicted that NiSi was not magnetic. As a result, researchers had never fully explored magnetism in NiSi. An international team of researchers (USA – University of Missouri, Oak Ridge National Laboratory, Austria, Poland) showed that NiSi metal could provide suitable new platform. The study showed high-temperature antiferromagnetism in single-crystal NiSi with Néel temperature. Antiferromagnetic order in NiSi was accompanied by non-centrosymmetric magnetic character with small ferromagnetic component in the a–c plane. It was found that NiSi manifests distinct magnetic […]
A thousand times smaller than a grain of sand—glass sensors 3D-printed on optical fiber
Phys.org May 15, 2024 Integration of functional materials and structures on the tips of optical fibers has enabled various applications in micro-optics. 3D printing technology holds promise for fabricating advanced micro-optical structures on fiber tips. Material selection has been limited to organic polymer-based photoresists because existing methods for 3D direct laser writing of inorganic materials involve high-temperature processing that is not compatible with optical fibers. Researchers in Sweden demonstrated 3D direct laser writing of inorganic glass with a subwavelength resolution on optical fiber tips. They showed two distinct printing modes that enabled the printing of solid silica glass structures “Uniform […]
Scientists discover a new type of porous material that can store greenhouse gases
Phys.org April 29, 2024 Researchers in the UK have developed a two-step, hierarchical synthesis that assembled a trigonal prismatic organic cage into a more symmetric, higher-order tetrahedral cage. Both the preformed [2+3] trigonal prismatic cage building blocks and the resultant tetrahedral [4[2+3]+6]cage molecule were constructed using ether bridges. This strategy afforded the tetrahedral cage molecule excellent hydrolytic stability that was not a feature of more common dynamic cage linkers. Despite its relatively high molar mass, tetrahedral cage exhibited good solubility and crystallized into a porous superstructure. By contrast, the [2+3] building block was not porous. The tetrahedral cage molecule showed […]
Topological phonons: Where vibrations find their twist
Phys.org May 9, 2024 Phonons play a crucial role in many properties of solid-state systems, and it is expected that topological phonons may lead to rich and unconventional physics. Based on the existing phonon materials databases an international team of researchers (USA – Princeton University, Spain) compiled a catalog of topological phonon bands for more than 10,000 three-dimensional crystalline materials. Using topological quantum chemistry, they calculated the band representations, compatibility relations, and band topologies of each isolated set of phonon bands for the materials in the phonon databases. They also calculated the real-space invariants for all the topologically trivial bands […]
Ultrasound experiment identifies new superconductor
Phys.org May 9, 2024 Uranium ditelluride (UTe2) has previously been inferred to have a multi-component order parameter, in part due to the apparent presence of a two-step superconducting transition in some samples. However, recent experimental observations in newer-generation samples have raised questions about this interpretation, pointing to the need for a direct probe of the order parameter symmetry. An international team of researchers (USA – Cornell University, University of Maryland, University of Wisconsin-Milwaukee, NIST, France, Canada) measured the elastic moduli of UTe2 in samples that exhibited both one and two superconducting transitions. They demonstrated the absence of thermodynamic discontinuities in […]