Material sciences

  • “Bethe Strings” Experimentally Demonstrated as Many-Body Quantum States for the First Time

    In SrCo₂V₂O₈ the cobalt ions (CO²⁺) form in the interior of a chain of edges-linked oxygen octahedra a quasi-one-dimensional electron spin chain with spin S = ½. © Universität Augsburg/IfP/EP V

    The synthesis of quasi one-dimensional magnets and their investigation by means of optical spectroscopy in extremely high magnetic fields led to success. Augsburg /AL/KPP - “Bethe strings” are excitations of strongly bound electron spins in one-dimensional quantum spin systems. These quantum spin states are named after the physicist Hans Bethe, who first described them theoretically in 1931.

  • “Electricity as a Raw Material” at ACHEMA 2018: Green Energy for Sustainable Chemistry

    Demonstrator for the production of ethene from CO2. Fraunhofer IGB

    Hydrogen peroxide, ethene, alcohols: The Fraunhofer lighthouse project “Electricity as a raw material” is developing electrochemical processes that use renewable electricity to synthesize basic chemicals - with the aim of making the chemical industry more sustainable. From June 11 to 15, Fraunhofer UM-SICHT will be presenting the results together with eight other Fraunhofer Institutes at ACHEMA 2018.

  • 10nm Pattern Generation Using Thermal Scanning Probe Lithography Enabled by Simplified Materials and Processes

    High resolution metal lines fabricated by means of lit-off process. (c) PiBond Oy

    Thermal scanning probe lithography (tSPL) has been used to create patterns with sub-20 nm half pitch resolution. Pattern generation uses a thermally sensitive resist and spin coatable hard mask materials to transfer the resist patterns. Spin coatable materials permit users of tSPL to reduce time and cost of the patterning process.

  • 3D printer inks from the woods

    Rod-like cellulose nanocrystals (CNC) approximately 120 nanometers long and 6.5 nanometers in diameter under the microscope. (Image: Empa)

    Empa researchers have succeeded in developing an environmentally friendly ink for 3D printing based on cellulose nanocrystals. This technology can be used to fabricate microstructures with outstanding mechanical properties, which have promising potential uses in implants and other biomedical applications.

    In order to produce 3D microstructured materials for automobile components, for instance, Empa researchers have been using a 3D printing method called “Direct Ink Writing” for the past year (DIW, see box). During this process, a viscous substance – the printing ink – is squeezed out of the printing nozzles and deposited onto a surface, pretty much like a pasta machine.

  • 3D-Druck: Maßgeschneiderte Einlegesohlen für Diabetes-Patienten

    3D-Strukturen aus TPU für Einlegesohlen. Die Strukturen wurden über CAD ausgelegt, ihre Eigenschaften simuliert und mit Experimenten abgeglichen. Fraunhofer IWM

    Einlegesohlen für Diabetes-Patienten stellen Orthopädieschuhtechniker bislang in Handarbeit her. Künftig können die Spezialisten die Sohlen kostengünstiger als bisher mit einer neuartigen Software entwerfen und mithilfe von 3D-Druckern herstellen. Die Vorteile: Die mechanischen Eigenschaften der Einlegesohlen lassen sich besser analysieren und wissenschaftlich bewerten. Drückt der Schuh? Üblicherweise verlagert man in diesem Fall das Gewicht und entlastet die schmerzende Stelle. Bei Diabetes-Patienten jedoch verkümmern oftmals die Nervenenden im Fuß – die Betroffenen spüren die schmerzende Stelle nicht. Dies kann zu Druckstellen und schließlich zu Wunden führen, die schlecht verheilen. Abhilfe oder zumindest Linderung versprechen Einlegesohlen, die an der verletzten Stelle sehr weich sind und die Orthopädieschuhtechniker in Handarbeit aus verschiedenen Materialien passgenau anfertigen.

  • A Burst of ”Synchronous” Light

    Superlattices under the microscope (white light illumination). Empa

    Excited photo-emitters can cooperate and radiate simultaneously, a phenomenon called superfluorescence. Researchers from Empa and ETH Zurich, together with colleagues from IBM Research Zurich, have recently been able to create this effect with long-range ordered nanocrystal superlattices. This discovery could enable future developments in LED lighting, quantum sensing, quantum communication and future quantum computing. The study has just been published in the renowned journal "Nature".

  • A Fine-tuned Laser Welds More Effectively

    Cardiac pacemakers are usually housed in a titanium housing that is welded together from two parts. Empa has optimized the frequency of the working laser so that no black edges appear during welding, which would reduce the value of the medical product. Image: istockphoto

    Using laser technology Empa scientists optimized a technique to weld the electronics of implantable pacemakers and defibrillators into a titanium case. The medtech company Medtronic is now using the method worldwide to produce these devices. In Tolochenaz (Canton of Vaud) the US medtech company Medtronic produces one out of five heart pacemakers available on the global market and one out of four defibrillators. The electronics of these implantable devic-es are housed in titanium cases, which thus far were welded hermetically with a solid state flash laser. However, the lasers are high-maintenance and often the source of irregularities. Moreover, they require water cooling and take up a lot of space.

  • A laser for divers

    Laser cutting of sheet piling under water. Photo: LZH

    Working under water is personnel- and time-intensive. The Laser Zentrum Hannover e.V. (LZH) is therefore working on developing a laser-based, automated process for cutting sheet piling under water, together with the Institute of Materials Science of the Leibniz Universität Hannover. Sheet piling protects fortified shore areas, or can be used to dry out these areas if repairs are necessary. If the sheet piling must be dismantled, divers must cut the walls into smaller pieces using a cutting torch. Normally, a diver can cut about 20 meters a day, which corresponds to a speed of about 0.07 meters per minute. In the project LuWaPro, scientists at the LZH have now developed a process which uses a disc laser for torch cutting. The divers thus only carries out a supervisory role. The process can be used to separate the metal sheets, which are usually 10 mm thick for sheet piling, at speeds of up to 0.9 m/min.

  • A Material with Promising Properties

    Picture of a hybrid particle taken by a transmission electron microscope. Pictured are the inorganic (dark) and organic (light) lamellas that the particle is made of, as well as the tubular shapes (the low-contrast area in the middle). Through vaporisation with Europium, the hybrid stage can be transformed into pure EuO. Copyright: University of Konstanz

    Konstanz scientist synthesises an important ferromagnetic semiconductor. The Collaborative Research Centre CRC 1214 at the University of Konstanz has developed a method for synthesising Europium (II) oxide nanoparticles - a ferromagnetic semiconductor that is relevant for data storage and data transport. Ferromagnetic semiconductors have attracted increasing attention over the last decade. Their properties make them promising functional materials that can be used in the field of spin-based electronics (spintronics). Spintronics is of crucial importance for the storage and transport of information.

  • A Materials Scientist’s Dream Come True

    Christian Dolle, Peter Schweizer und Prof. Dr. Erdmann Spiecker (von links nach rechts) beim anipulieren von Versetzungen an ihrer Nano-Werkbank, einem erweiterten Elektronenmikroskop. Mingjian Wu

    In the 1940s, scientists first explained how materials can deform plastically by atomic-scale line defects called dislocations. These defects can be understood as tiny carpet folds that can move one part of a material relative to the other without spending a lot of energy. Many technical applications are based on this fundamental process, such as forging, but we also rely on the power of dislocations in our everyday life: in the crumple zone of cars dislocations protect lives by transforming energy into plastic deformation. FAU researchers have now found a way of manipulating individual dislocations directly on the atomic scale – a feat only dreamt of by materials scientists.

  • A New Knob to Control and Create Higher Harmonics in Solids

    When exciting crystals such as silicon by an intense elliptically or circularly polarized light pulse (red), circularly polarized higher harmonics (green & blue) can be generated. Nicolas Tancogne-Dejean + Joerg M. Harms, MPSD

    Scientists at the MPSD and CFEL have demonstrated the possibility of using a new knob to control and optimize the generation of high-order harmonics in bulk materials, one of the most important physical processes for generating high-energy photons and for the ultrafast manipulation of information.

  • A new spin on electronics

    The spin of electrons transports information in this conducting layer between two isolators. Image: Christoph Hohmann / NIM

    Interface between insulators enables information transport by spin.
    Modern computer technology is based on the transport of electric charge in semiconductors. But this technology’s potential will be reaching its limits in the near future, since the components deployed cannot be miniaturized further. But, there is another option: using an electron’s spin, instead of its charge, to transmit information. A team of scientists from Munich and Kyoto is now demonstrating how this works.

  • A Space-Time Sensor for Light-Matter Interactions

    By using trains of extremely short electron pulses, LAP researchers have obtained time-resolved diffraction patterns from crystalline samples. In this image, patterns captured at attosecond intervals have been superimposed, thus revealing, in real time, the kind of electron motions that underlie atomic and subatomic phenomena. (Photo: Baum/Marimoto)

    Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms. The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a billionth of a second). What exactly happens in such an astonishingly short time has so far remained largely inaccessible.

  • A Transistor of Graphene Nanoribbons

    The microscopic ribbons lie criss-crossed on the gold substrate. Empa

    Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications." Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the nanoelectronics of the future:

  • A Transparent and Thermally Stable Polyamide – 100 Percent Biobased

    From wood waste to high-performance polymers: Terpenes from turpentine are converted to bio-based, transparent and heat-stable polyamides under application of a new catalytic process. Fraunhofer IGB

    The natural substance 3-carene is a component of turpentine oil, a waste stream of the production of cellulose from wood. Up to now, this by-product has been incinerated for the most part. Fraunhofer researchers are using new catalytic processes to convert 3-carene into building blocks for biobased plastics. The new polyamides are not only transparent, but also have a high thermal stability.

  • A Water-Based, Rechargeable Battery

    Research on the water electrolyte: Empa researcher Ruben-Simon Kühnel connecting a test cell to the charger with the concentrated saline solution. Empa

    Water could form the basis for future, particularly inexpensive rechargeable batteries. Empa researchers have succeeded in doubling the electrochemical stability of water with a special saline solution. This takes us one step closer to using the technology commercially. In the quest to find safe, low-cost batteries for the future, eventually we have to ask ourselves a question: Why not simply use water as an electrolyte? 

  • Active Implants: How Gold Binds to Silicone Rubber

    Thin film preparation scheme. a) Cross section of the organic molecular beam deposition setup for the fabrication of soft multi-layer nanostructures under ultra-high vacuum conditions. In situ spectroscopic ellipsometry at an incident angle of 20° simultaneously monitors film thickness, optical properties, and plasmonics. Representative schemes of thermally grown soft nanostructures: b) self-assembled Au particles bound to bi-functional, thiol-terminated PDMS; c) wrinkled Cr/PDMS; d) Au nanoparticles on a PDMS membrane. Coherent electron oscillations occur if the nanoparticles become excited at the resonance frequency. Due to the incident 4 × 10 mm2 beam dimension, SE monitors nanostructures over a macroscopic area. (© Wiley-VCH Verlag)

    Flexible electronic parts could significantly improve medical implants. However, electroconductive gold atoms usually hardly bind to silicones. Researchers from the University of Basel have now been able to modify short-chain silicones in a way, that they build strong bonds to gold atoms. The results have been published in the journal «Advanced Electronic Materials».

    Ultra-thin and compliant electrodes are essential for flexible electronic parts. When it comes to medical implants, the challenge lays in the selection of the materials, which have to be biocompatible. Silicones were particularly promising for application in the human body because they resemble the surrounding human tissue in elasticity and resilience. Gold also poses an excellent electrical conductivity but does only weakly bind to silicone, which results in unstable structures.

  • Added Disorder Drives Transition to Photonic Topological Insulator

    A honeycomb waveguide structure with helical waveguides acts as a photonic topological insulator so that light is guided along the surface. Copyright: University of Rostock/Alexander Szameit, Lukas Maczewsky

    As the journal Nature reported recently, a research group led by the Rostock physicist Professor Alexander Szameit, in collaboration with colleagues in Israel and the U.S., experimentally demonstrated that a messy topological insulator can be restored in its properties by inducing random disorder.

  • Additive manufacturing, from macro to nano

    Magnesium part produced with selective laser micro melting.  Photo: LZH

    Creating large structures with high volume or with the highest-possible resolution: The Laser Zentrum Hannover e.V. (LZH) is carrying out research on diverse processes for additive manufacturing, in order to push past the present limits. At the Hannover Messe 2017, at the pavilion of the State of Lower Saxony (hall 2, stand A08), the LZH is presenting the state of the art.

    Light for Innovation – since 1986, the Laser Zentrum Hannover e.V. (LZH) has been committed to advancing laser technology. Supported by the Lower Saxony Ministry for Economics, Labour and Transport, the LZH has been devoted to the selfless promotion of applied research in the field of laser technology.

  • Additive Manufacturing: Budget-friendly Retrofit of Module for Wire-based Laser Deposition Welding

    Processing head "LMD-W-20-L" for wire-based laser deposition welding. Graphic: Fraunhofer IPT

    When economic or safety considerations rule out the use of powder materials in additive manufacturing, the option of wire-feed laser deposition welding resents itself. The Fraunhofer Institute for Production Technology IPT in Aachen has developed a smart laser module for wire deposition welding, which can easily be integrated within existing process chains, handling systems or machine tools. The engineers from Aachen will be unveiling the LMD-W-20-L module for the first time to the visitors from industry at Formnext, the Fair for Additive Technologies in Frankfurt/Main, Hall 3, Booth E70, 13-16 November 2018.