Nanowerk June 28, 2021 An international team of researchers (Australia, China) demonstrated that ultra-high electron doping concentration (above 1021 cm-3) can be induced in the layered van der Waals (vdW) metallic material Fe5GeTe2 by proton intercalation and can further cause a transition of the magnetic ground state from ferromagnetism to antiferromagnetism. Compared to itinerant ferromagnets, antiferromagnets (AFMs) have unique advantages as building blocks of such future spintronic devices. Their robustness to stray magnetic fields makes them suitable for memory devices. All the samples showed that the ferromagnetic state can be gradually suppressed by increasing proton intercalation, and finally several samples […]
Tag Archives: Advanced materials
The first observation of the superscattering effect of metamaterials
Phys.org June 23, 2021 Superscattering effects, such as stopping wave propagation in an air channel, have not been verified from illusion devices physically because of the challenge of metamaterial design, fabrication, and material loss. Researchers in China have implemented a big metamaterial superscatterer, and experimentally demonstrated its superscattering effect at microwave frequencies by field-mapping technology. They confirmed that superscattering is originated from the excitation of surface plasmons. They experimentally showed that an invisible gateway integrated with superscatterer could stop electromagnetic waves in an air channel with a width much larger than the cutoff width of the corresponding rectangular waveguide. The […]
Cameras and telescopes as thin as a sheet of paper?
Nanowerk June 10, 2021 Metalenses promise to make imaging devices more compact. An international team of researchers (Canada, USA – University of Rochester) has addressed the space between the lenses which is crucial for image formation but takes up by far the most room in imaging systems, by introducing the idea of a spaceplate. They experimentally demonstrated that it is compatible with broadband light in the visible spectrum. They manipulated light based on the angle rather than the position of a light ray. Angle is a completely novel domain. They designed and experimentally demonstrated plates that compressed the space. Such […]
In a nano-optics breakthrough, researchers observe sound-light pulses in 2D materials (w/video)
Nanowerk June 10, 2021 An international team of researchers (Israel, Spain, France, USA – Kansas State University) shone pulses of light along the edge of a 2D material, producing in the material the hybrid sound-light waves. Not only were they able to record these waves, but they also found the pulses could spontaneously speed up and slow down. Surprisingly, the waves even split into two separate pulses, moving at different speeds. They developed a new technique to image the motion of light without disturbing it. According to the researchers having access to the full spatiotemporal dynamics of 2D wave packets […]
Lead halide perovskites – a horse of a different color
Nanowerk June 7, 2021 To capture the full range of the photophysical processes that occur in metal halide perovskites an international team of researchers (Sweden, Russia, Germany) has developed a novel spectroscopic technique for the study of charge carrier dynamics in lead halide perovskites. This methodology is based on the complete mapping of the photoluminescence quantum yield and decay dynamics in the 2D space of both fluence and frequency of the excitation light pulse. They offer a complete representation of the sample’s photo physics, allow examining the validity of theories by applying a single set of theoretical equations and parameters to […]
Online ‘library of properties’ helps to create safer nanomaterials
Nanowerk June 8, 2021 Under the European Union H2020-funded NanoSolveIT project an international team of researchers (Cyprus, UK) has developed a decision support system in the form of both stand-alone open software and a freely available cloud library containing full physicochemical characterisation of 69 nanomaterials, plus calculated molecular descriptors to increase the value of the available information. The dataset contains over 70 descriptors per nanomaterial. Over the last two years, this project has already presented some very impressive results with more than 30 publications, making NanoSolveIT one of the most active projects in the nanomaterials safety and informatics space. The […]
A quantum step to a heat switch with no moving parts
Science Daily June 7, 2021 Based on foundational theory a team of researchers in the US (Iowa State University, University of Ohio, University of Chicago) engineered an alloy with the elements bismuth and antimony at precise ranges. In this material electrons move like massless photons, a phenomenon theoretically predicted to exist. Under the influence of an external magnetic field some of the electrons generate energy, while others absorb energy, effectively turning the material into an energy pump resulting in 300% increase in its thermal conductivity. The mechanism is turned off if the magnet is taken away. This property, and the […]
Ultra-high-density hard drives made with graphene ‘overcoats’ store ten times more data
Nanowerk June 7, 2021 Currently, carbon-based overcoats (COCs), layers used to protect platters from mechanical damages and corrosion, occupy a significant part of this spacing. An international team of researchers (India, Singapore, UK, USA – Argonne National Laboratory, University of Illinois, Switzerland) replaced commercial COCs with one to four layers of graphene which fulfills all the ideal properties of an HDD overcoat in terms of corrosion protection, low friction, wear resistance, hardness, lubricant compatibility, and surface smoothness. They transferred graphene onto hard disks made of iron-platinum as the magnetic recording layer, and tested Heat-Assisted Magnetic Recording (HAMR) that enables an […]
New quantum material discovered
Nanowerk May 26, 2021 Usually, quantum critical behaviour is studied in metals or insulators. But an international team of researchers (USA – Johns Hopkins University, University of Maryland, NIST, Rice University, Austria) looked at a semimetal which is a compound of cerium, ruthenium, and tin – with properties that lie between those of metals and semiconductors. Usually, quantum criticality can only be created under specific environmental conditions however, this semimetal turned out to be quantum critical without any external influences at all. They suspect that it may be because it has a highly correlated electron system where the electrons interact […]
Quantum electronics: ‘Bite’ defects in bottom-up graphene nanoribbons
Science Daily May 25, 2021 Researchers in Switzerland have shown the nature of the structural disorder in bottom-up zigzag graphene nanoribbons along with its effect on the magnetism and electronic transport based on scanning probe microscopies and first-principles calculations. They found that edge-missing m-xylene units emerging during the cyclodehydrogenation step of the on-surface synthesis are the most common point defects. These “bite” defects act as spin-1 paramagnetic centers, severely disrupting the conductance spectrum around the band extrema, and give rise to spin-polarized charge transport. They also showed that the electronic conductance across graphene nanoribbons is more sensitive to “bite” defects […]