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  • richardmitnick 5:10 pm on September 22, 2014 Permalink | Reply
    Tags: , , Material Sciences,   

    From BNL:”Growth of an Ultra-thin Layered Structure Offers Surprises” 

    Brookhaven Lab

    September 22, 2014
    Laura Mgrdichian

    Many new technologies are based on ultra-thin layered structures that are “grown” using precise deposition techniques. Understanding and ultimately controlling this growth at the atomic level – particularly at the interfaces between these layers, where key properties arise – is essential to imparting these structures with properties tailored to possible applications.

    Researchers from the University of Vermont recently investigated an example of “heteroepitaxial” growth, in which one material is grown on the surface of a second material that has a similar crystal structure as the first. They studied a system of bismuth ferrite (BiFeO3, or BFO) grown on strontium titanate (SrTiO3, or STO). The research is published in the February 20, 2014, edition of Physical Review Letters.

    two
    Simulated “maps” for growing bismuth ferrite on strontium titanate

    BFO is a target for materials science researchers because of its diverse ferroelectric properties and possible applications in developing technologies such as nonvolatile memory and data storage. At the National Synchrotron Light Source, the researchers discovered that the BFO forms clusters that grow and coalesce into a single layer in an unexpected way. They found that their data agree well with the “interrupted coalescence model” (ICM) of layer growth. This finding was a bit of a surprise, but they propose that the model may be applicable to other layered systems.

    BNL NSLS
    BNL NSLS Interior
    NSLS

    “In this system, we saw compact, two-dimensional islands come together efficiently over a range of length scales,” said the study’s corresponding scientist, University of Vermont physicist Randall Headrick. “However, the kinetics of the growth process behave more like droplets than what we expected to observe, which was single-layer clusters that grow exponentially in time. This growth mode has implications for the structure of interfaces and ferroelectric domains in these materials, which will have an impact on domain switching in devices.”

    Headrick and his colleagues used a technique called sputter deposition to apply the BFO atoms to the STO surface and “watched” the growth of the BFO layer using x-ray diffraction at NSLS beamline X21. They saw the BFO quickly form islands of varying sizes, with an average size of about 20 nanometers. The small clusters retained their compact shape as they coalesced into bigger clusters. But, this coalescence was kinetically “frozen” when the clusters reached a critical size, leading to the formation of large connected irregularly shaped regions. In the spaces between, smaller islands continued to form and dot the area.

    The group confirmed these observations by studying the final layered structure with atomic force microscopy and additional x-ray diffraction measurements.

    afm
    Atomic Force Microscope at Rutgers University

    This work was supported by the
    Office of Basic Energy Sciences within the U.S. Department of Energy’s Office of Science.

    See the full article here.

    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 8:38 am on September 12, 2014 Permalink | Reply
    Tags: , Material Sciences, ,   

    From Stanford: “Stanford engineers help describe key mechanism in energy and information storage” 

    Stanford University Name
    Stanford University

    September 11, 2014
    Bjorn Carey

    By observing how hydrogen is absorbed into individual palladium nanocubes, Stanford materials scientists have detailed a key step in storing energy and information in nanomaterials. The work could inform research that leads to longer-lasting batteries or higher-capacity memory devices.

    block
    The palladium nanocubes viewed through a transmission electron microscope. Each black dot is a palladium atom.

    The ideal energy or information storage system is one that can charge and discharge quickly, has a high capacity and can last forever. Nanomaterials are promising to achieve these criteria, but scientists are just beginning to understand their challenging mechanisms.

    Now, a team of Stanford materials scientists and engineers has provided new insight into the storage mechanism of nanomaterials that could facilitate development of improved batteries and memory devices.

    The team, led by Jennifer Dionne, assistant professor of materials science and engineering at Stanford, and consisting of Andrea Baldi, Tarun Narayan and Ai Leen Koh, studied how metallic nanoparticles composed of palladium absorbed and released hydrogen atoms.

    Previously, scientists have studied hydrogen absorption in ensembles of metallic nanoparticles, but this approach makes it difficult to infer information about how the individual nanoparticles behave. The new study reveals that behavior by measuring the hydrogen content in individual palladium nanoparticles exposed to increasing pressures of hydrogen gas.

    The group’s experimental findings are consistent with a mechanism recently proposed for energy storage in lithium ion batteries, underscoring the interest for the broader scientific community. The work is detailed online in the journal Nature Materials.

    The finding was made possible by the use of a specialized transmission electron microscope (TEM) that allowed the team to detect, with near atomic-scale resolution, the process by which hydrogen entered the nanomaterial.

    “Electron microscopy must ordinarily be conducted in high vacuum,” said co-author Ai Leen Koh, a research scientist with the Stanford Nano Shared Facilities. “But the unique capabilities of Stanford’s environmental TEM obviates this requirement, enabling the study of individual nanoparticles both in vacuum and while immersed in a reactive gas.”
    Stretching metal

    The researchers synthesized palladium nanocubes and then dispersed them onto a very thin membrane. After placing the membrane in the TEM, the engineers flowed hydrogen gas past the palladium nanoparticles and gradually increased its pressure.

    At sufficiently high pressures of hydrogen, the gas molecules dissociate on the surface of the nanocubes and individual hydrogen atoms enter into the spaces between the palladium crystals. Interestingly, the absorption and desorption processes appear to be quite sudden.

    “You can think of it like popcorn,” said co-lead author Tarun Narayan, a graduate student in Dionne’s group. “It’s a very binary process, and a pretty sharp transition. Either the hydrogen is in the palladium or it’s not, and it enters and leaves at predictable pressures. And that’s quite important for a good energy storage system.”

    As the hydrogen enters the palladium nanostructure, the material’s volume increases by about 10 percent. This expansion significantly alters the way in which the particle interacts with the electron beam; this disruption indicates the amount of hydrogen absorbed. Because the nanocubes are single-crystalline and effectively “unbound” from the membrane, the researchers were able to study and measure the storage mechanism in unprecedented detail.

    “You have to stretch the palladium to put the hydrogen inside, but you have to pay energy to make it stretch,” said Andrea Baldi, a postdoctoral researcher in Dionne’s group. “Knowing that cost is very important for any battery designs, and because our nanostructures are not glued to a substrate, we’re able to quantify that stretch more accurately than ever before.”
    Next up: Palladium spheres

    Despite the stress of repeated expansion and contraction, the nanocrystals of palladium were not damaged by hydrogen absorption and desorption, as usually happens in larger specimens.

    “At the nanoscale, materials behave quite differently than they do in bulk,” said Dionne, the senior author. “Their increased surface area to volume ratio can significantly impact their mechanical flexibility and, consequently, their ability to charge and discharge ions or atoms.”

    In particular, this research indicates that nanoparticles can load more easily and at much lower pressures than bulk materials. Further, because they have a higher resistance to elastic stress, the formation of defects in these materials is suppressed.

    “Our results suggest that particles in this size regime don’t develop defects even if charged and discharged with hydrogen multiple times,” Narayan said. “Other researchers are starting to see this in lithium ion battery research as well, and we think a lot of what we’ve learned can be applied to that research.”

    Because of its fast storage speeds, stability and ease-of-loading, the hydrogenation of palladium is an excellent model system to study general energy and information storage mechanisms. Palladium, however, is not a likely material for widespread energy storage – it is too heavy and expensive. Yet, the researchers believe the results could be replicated with other systems involving storing hydrogen in metals.

    The next steps involve applying the newly developed single-particle method to a wide range of nanostructures – spheres and rods, for example – to study how storage can be affected by the shape, size and crystallinity of a nanoparticle. Furthermore, they plan to use the electron microscope to determine exactly where atoms or ions are preferentially absorbed within a singe nanoparticle.

    Dionne is an affiliate of the Stanford Institute for Materials and Energy Sciences (SIMES) and SLAC National Accelerator Laboratory. The research was supported by funding from the National Science Foundation, the Air Force Office of Scientific Research, the U.S. Department of Energy, a Young Energy Scientist Fellowship and a Hellman Fellowship.

    See the full article here.

    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

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  • richardmitnick 3:27 pm on September 11, 2014 Permalink | Reply
    Tags: , Material Sciences, ,   

    From M.I.T Tech: “A Super-Strong and Lightweight New Material” 

    MIT Technology Review
    M.I.T Technology Review

    September 11, 2014
    Katherine Bourzac

    Nanostructured ceramics could be used to build lighter, stronger airplanes and batteries.

    A new type of material, made up of nanoscale struts crisscrossed like the struts of a tiny Eiffel Tower, is one of the strongest and lightest substances ever made.

    mtl
    Tiny trusses: A scanning electron microscope image of the new material reveals its ceramic nano-lattices

    If researchers can figure out how to make the stuff in large quantities, it could be used as a structural material for making planes and trucks, as well as in battery electrodes.

    Researchers led by Caltech materials scientist Julia Greer found that by carefully designing nanoscale struts and joints, they could make ceramics, metals, and other materials that can recover after being crushed, like a sponge. The materials are very strong and light enough to float through the air like a feather. The work is published today in the journal Science.

    In conventional materials, strength, weight, and density are correlated. Ceramics, for example, are strong but also heavy, so they can’t be used as structural materials where weight is critical—for example, in the bodies of cars. And when ceramics fail, they tend to fail catastrophically, shattering like glass.

    But at the nanoscale the same rules do not apply. In this size range, the structural and mechanical properties of ceramics become less tied to properties such as weight, and they can be altered more precisely.

    “For ceramics, smaller is tougher,” says Greer, who was named one of MIT Technology Review’s 35 Innovators Under 35 in 2008 for her work on nanoscale mechanics. This means that nanoscale trusses made from ceramic materials can be both very light—unsurprising, since they are mostly air—and extremely strong.

    In 2011, working with researchers at HRL Laboratories, a private engineering research company, Greer created one of the lightest materials ever made, a microlattice of hollow metal tubes. She later chose to take on the greater challenge of making ceramics with similar properties. This required fine-tuning structures at the nanoscale, meaning the materials are even more difficult to produce.

    To make the ceramic nano-trusses, Greer’s lab uses a technique called two-photon interference lithography. It’s akin to a very low-yield 3-D laser printer.

    First they use this method to create the desired structure, a lattice, out of a polymer. The polymer lattice is then coated with a ceramic such as alumina. Oxygen plasma etches out the polymer, leaving behind a lattice of hollow ceramic tubes.

    Greer’s lab showed that by changing the thickness of the tube walls, it’s possible to control how the material fails. When the walls are thick, the ceramic shatters under pressure as expected. But trusses with thinner walls, just 10 nanometers thick, buckle when compressed and then recover their shape.

    “You don’t expect these materials to recover—you expect them to be brittle and to fracture,” says Christopher Spadaccini, an engineer who specializes in materials manufacturing at the U.S. Department of Energy’s Lawrence Livermore National Laboratory in California.

    The new materials might be particularly interesting for use in batteries, notes Nicholas Fang, a mechanical engineer at MIT who is also working on nanostructured ceramics. Nanostructures have a very high surface area and are lightweight, a combination that could make for a fast-charging battery that stores a lot of energy in a convenient package. In fact, Greer says she is collaborating with German electronics company Bosch to apply her designs to lithium-ion batteries.

    See the full article here.

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  • richardmitnick 8:56 am on September 11, 2014 Permalink | Reply
    Tags: , , Material Sciences   

    From M.I.T.Tech: “No More Cracked Smartphone Glass” 

    MIT Technology Review
    M.I.T Technology Review

    September 11, 2014
    Kevin Bullis
    Photographs by Ken Richardson

    Ultrathin sapphire laminates could lead to durable but affordable next-generation screen covers.

    Glass touch-screen displays are easily cracked and scratched, making them a weak point in today’s ubiquitous mobile devices. Sapphire—second only to diamond in hardness—could make such damage a thing of the past. Sapphire is already used on a few luxury smartphones and for small parts of recent iPhones, including the cover of the camera lens and thumbprint reader on the iPhone 5S. And some models of Apple’s newly announced watch include a sapphire face. In a sign of the material’s growing importance, Apple recently invested $700 million in a sapphire processing factory in Arizona.

    The problem is that sapphire costs five to 10 times as much as the toughened glass used now in almost all smartphones, limiting its use to small screens or specialized devices. But in Danvers, Massachusetts, engineers at GT Advanced Technologies say they are solving the cost problem with a new manufacturing process that cheaply and efficiently produces sheets of sapphire just a quarter as thick as a piece of paper. These sheets, when laminated to a conventional glass display, can do a lot to prevent damage, since it only takes a very thin layer of sapphire to prevent scratches and to resist cracks when a phone is dropped.

    start
    Top: The process starts with a slab of sapphire more than a millimeter thick.
    Above Left to right: A technician loads circular wafers of sapphire into a template, then loads that into a high-power ion ­accelerator.

    blue
    The template glows blue as it’s irradiated by hydrogen ions traveling at nearly 20,000 kilometers per second.

    accel
    The ion accelerator (right side of image) shoots ions through metal tubes to a target on the left.

    three
    Top: The accelerator includes three rows of nine generators and power supply modules.

    left
    Left: One of the generators is tested.
    Center: A power supply converts low-voltage electricity to high-voltage.

    demo
    A wafer-handling system, like this one for silicon wafers, will allow high-throughput production of sapphire laminate.

    two
    Left: In the high heat of a gold-plated oven, the injected ions form hydrogen bubbles that cause the sapphire wafer (at right side of black platform) to slough off a thin layer of sapphire (at center of platform).
    Above top: The resulting sheet is just 26 micrometers thick.
    Above bottom: A laminating machine affixes sapphire to glass.

    disc
    A finished disk of sapphire (inner circle) now covers the glass.

    The company’s process can make about 10 sapphire sheets from the same amount of material that would go into just one solid display. That could help make sapphire ubiquitous in smartphones. Indeed, it would probably only add a few dollars to the cost of a phone. And it could allow sapphire to be used on displays for larger devices, such as tablets.

    GT Advanced Technologies is already a major sapphire supplier, having built the Arizona plant for Apple. The facility in Danvers is devoted to a next-generation manufacturing process. Behind the process is a machine called an ion accelerator, the size of a cement mixing truck. The machine generates two million volts of electricity and flings hydrogen ions at sapphire crystal wafers, embedding the ions at a precise depth in the sapphire. Then the material is heated in an oven, causing hydrogen bubbles to form within it and ultimately forcing a layer of sapphire to pop off. When that layer is polished, it becomes transparent.

    Though ion accelerators are already used to modify the properties of semiconducting materials, GT Advanced Technologies had to develop a machine 10 times more powerful in order to embed ions deeply and precisely enough to produce usable sheets of sapphire. The method is a big improvement over conventional means of making thin sapphire sheets, which involve sawing up a large chunk of sapphire into wafers and then grinding them down. That process wastes a lot of costly sapphire and, at the same time, introduces defects that make the thin sheets easy to break.

    Ted Smick, the company’s vice president of equipment engineering, expects his ion accelerator to be ready for market next year, after he develops an automated system for moving sapphire through the process. Eventually, the technology could help make sapphire-coated displays commonplace, making many of the hundreds of millions of smartphones sold each year far more durable.

    See the full article here.

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  • richardmitnick 8:23 am on September 11, 2014 Permalink | Reply
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    From M.I.T. Tech: “Manufacturing Advances Mean Truly Flexible Devices Are on the Way” 

    MIT Technology Review
    M.I.T Technology Review

    September 11, 2014
    Kevin Bullis

    The technology needed to make flexible displays, electronics, and batteries is being tested.

    One of the innovations packed inside the Apple Watch—and highlighted by designer Jony Ive at the company’s grand unveiling this week—is a flexible display.

    Contrary to some earlier speculation about the device, however, this doesn’t mean you can actually bend the screen. As with other devices featuring flexible displays, such as those from LG and Samsung, the display has been laminated onto a stiff pane, fixing it in place to prevent the damage that would come from repeated flexing.

    sam
    Flexible future: Samsung showed off flexible display prototypes in 2013.

    Even so, the appearance of the first few flexible screens in commercial devices may be a sign of things to come. In fact, fully flexible electronic gadgets—with full-color displays that wrap around a wrist or fold up—may be just a few years away, thanks to solutions that manufacturers have already started to demonstrate.

    Apple hasn’t disclosed why the Apple Watch has a flexible display. It might allow for a slight curve at the edges, and it may also simply be thinner than a conventional one

    In a conventional LCD display the liquid crystals within the pixels need to be perfectly positioned between two sheets of glass. These sheets cannot be bent without misaligning the pixels. According to Max McDaniel, chief marketing officer for Applied Materials, a company whose equipment is used to make displays, is also extremely difficult to make a flexible backlight—the component needed to illuminate LCD pixels.

    So the screen in the Apple Watch is almost certainly an OLED display. Rather than the pixels being illuminated by a backlight, each pixel glows on its own, like a minuscule light bulb. Manufacturers can already make OLED displays flexible. They first laminate a sheet of plastic to glass and then deposit the materials for the pixels and the electronics on top of both. The glass stabilizes the manufacturing process, and afterwards the plastic, together with display and electronic components, is lifted off the glass.

    Manufacturers have known how to do this for years. Samsung showed off a fully flexible OLED display in 2013. The tricky part is making sure the devices are durable. OLED pixels can be destroyed by even trace amounts of water vapor and oxygen, so you have to seal the display within robust, high-quality, flexible materials. This is costly, and there are challenges with ensuring that the seal survives being bent hundreds or thousands of times over the lifetime of a device.

    The parts within a flexible display also need to survive being bent. This is tricky because different layers—the battery, the electronics, and the touch components—tend to be stacked, and the innermost layers have to bend more than the outermost ones. The outer layers also stretch while the inner ones compress.

    Some researchers have developed stretchable electronics, which might help accommodate stresses (see “Stretchable Displays” and “Making Stretchable Electronics”). Novel materials for touch screens that use flexible nanomaterials could also help. One patent application suggests Apple is already looking at this issue. It describes measures such as varying the thickness of materials in a device to allow it to bend while keeping the electronics lined up properly with the pixels they control.

    Making a flexible battery is another challenge. While the lithium-polymer batteries used in smartphones today are somewhat flexible, they can’t survive being bent many times. One option is to make a segmented battery, like a segmented watch band, says Kevin Chen, general manager for energy storage solutions at Applied Materials. His company is developing solid-state batteries, which could easily be cut up into small pieces for flexible devices, and which also have the potential to store much more energy than conventional lithium-ion batteries (see “Longer-Lasting Battery Is Being Tested for Wearable Devices”). Apple outlines a similar battery design in another recent patent application.

    Steady progress means fully flexible devices could be available in just a few years. Meanwhile, we have flexible displays that are fixed in place—as in the Apple Watch.

    See the full article here.

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  • richardmitnick 8:03 am on September 11, 2014 Permalink | Reply
    Tags: , Material Sciences,   

    From physicsworld.com: “Fractal-like honeycombs take the strain” 

    physicsworld
    physicsworld.com

    Sep 10, 2014
    Katherine Kornei

    Honeycomb lattices and fractal structures are found in a range of biological materials. Now, scientists in the US, the UK and France have combined the two types of pattern to create a strong and lightweight material that could be used in a range of applications, from aerospace to medicine. While the structures were made with centimetre-sized unit cells, the team believes that similar materials could be made on the nanoscale using carbon nanotubes.

    test
    Photograph of a fractal-like honeycomb structures being tested
    Under pressure

    Hexagonal honeycomb patterns often appear in nature, where strength, rigidity and lightness are called for. The shells of armadillos, the beaks of birds and, of course, the wax cells built by bees are just a few examples of nature’s honeycombs. Engineers have long known about the honeycomb’s strength and low density, and the structure has been used in applications as varied as satellite components and the scaffolding for growing new heart tissue.

    Now, Ashkan Vaziri and colleagues at Northeastern University, along with researchers at the University of Oxford and the Université de Lyon, have shown that fractal-like structures based on honeycombs are even more resistant to deformation than conventional honeycomb materials.

    Hierarchical structures

    Fractals – in which the same patterns appear on different length scales – are also found in a variety of naturally occurring materials, including the buds on certain types of broccoli, pinecone seeds and nautilus shells. “Hierarchical structures are ubiquitous in nature and can be observed at many different scales in organic materials and biological systems,” explains Vaziri. Honeycombs on their own are not fractals because their characteristic shape only occurs on one length scale. However, a hierarchical fractal structure can be built upon a hexagonal honeycomb by successively replacing each vertex of three edges with another, smaller hexagon (see the image below).

    Vaziri and collaborators looked at how the mechanical properties of these hierarchical hexagonal honeycombs varied as a function of how many times the fractal order was repeated. The team used both MATLAB computer models and experimental testing to study the structural performance of the hierarchical hexagonal honeycombs. Specifically, the researchers looked at the elements of the structure that can undergo stretching, shear and bending. “Our goal is to develop novel, hierarchical structures that are far superior to the classical cellular structures in terms of their mechanical response,” Vaziri told physicsworld.com.

    Reaching a limit

    The computer simulations focused on the elastic modulus of each structure, which measures a material’s ability to resist deformation. To make a meaningful comparison between structures comprising different numbers of hexagonal hierarchies, the team adjusted the thickness of each structure to ensure that they all had the same density.

    “Generally, increasing the density of the cellular structure while preserving its topology improves the mechanical properties of the structure,” Vaziri explains. “To solely investigate the effect of hierarchical order on the mechanical properties of the hierarchical structure, we preserve the relative density while increasing the hierarchical order.”

    The simulations predict that the elastic moduli of the structures increase with hierarchical order, up to a certain threshold. Furthermore, the calculations suggest that materials with desirable elastic moduli can be manufactured without having to resort to extremely high orders of hierarchy. This is good news from a practical point of view, because it would be difficult to achieve high orders of hierarchy using today’s 3D printing technologies.

    Making it real

    The next step for Vaziri’s team was to test its findings in the lab. The researchers used a 3D printer to manufacture extruded polymer shells of five honeycomb structures, each with a successively higher order of hierarchy. The thickness of the honeycomb walls was maintained at 2 mm because of limitations of the 3D printing process. To maintain a constant density, the size of the unit cells was adjusted instead of the thickness.
    Photograph of fractal-like honeycomb unit cells

    comb
    Honeycombs within honeycombs: unit cells made by a 3D printer

    The hexagonal edge lengths of the extruded structures ranged from 0.6 to 2.2 cm. The researchers tested the compressive response and elastic modulus of each structure, recording how each structure’s resistance to deformation varied as a function of its hierarchy. The results revealed that, as predicted by the simulations, structures with a higher order of hierarchy had increasingly larger elastic moduli, to a certain limit.

    Even though Vaziri and his team focused on unit cells that were on the centimetre length scale, they are confident that their findings can be applied to smaller scales. “The unit cells of the hierarchical honeycombs can be built with single- or multi-walled carbon nanotubes,” Vaziri claims. Deformation-resistant structures assembled from carbon nanotubes would have widespread applications in biological engineering and materials science.

    The structures are described in Physical Review Letters.

    See the full article here.

    PhysicsWorld is a publication of the Institute of Physics. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

    We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
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  • richardmitnick 9:00 pm on September 10, 2014 Permalink | Reply
    Tags: , , Material Sciences   

    From ESA: “Europe’s New Age of Metals Begins” 

    ESASpaceForEuropeBanner
    European Space Agency

    10 September 2014
    No Writer Credit

    ESA has joined forces with other leading research institutions and more than 180 European companies in a billion-euro effort developing new types of metals and manufacturing techniques for this century.

    Known as Metallurgy Europe, the seven-year international research and development programme was launched at London’s Science Museum on Tuesday.

    “We’ll be laying the technical foundations for the discovery of new materials – metallic compounds, alloys, composites, superconductors and semiconductors,” explained Prof. David Jarvis, Head of Strategic and Emerging Technologies at ESA and Chairman of Metallurgy Europe.

    “We’ll also be applying computer modelling to guide our alloy creation, as well as advanced manufacturing techniques, such as additive manufacturing or 3D printing, for the creation of new products.”

    dj
    Prof. David Jarvis

    From the Iron Age to the Nuclear Age, metallurgy has been a driving force in human history. The various branches of the metals-related industry today accounts for 46% of the EU’s manufacturing value and 11% of its total Gross Domestic Product – equivalent to €1.3 trillion annually or €3.5 billion daily.

    Metallurgy Europe is conservatively projected to create at least 100 000 new jobs, based on the 10 million people today employed by the metals and end-user industries across the EU plus Switzerland and Norway.

    Organised along 13 topics, the potential results include novel heat-resistant alloys for space and nuclear systems, high-efficiency power lines based on superconducting alloys, thermoelectric materials converting waste heat into power, new catalysts for the production of plastics and pharmaceuticals, bio-compatible metals for medical implants, as well as high-strength magnetic systems.

    3d
    3D-printed aeronautics demonstrator

    Lightweight alloys and composites for the aerospace and automotive industries could potentially slash the weight of spacecraft components, as well as reduce today’s two-tonne cars by more than half.

    “The periodic table gives us around 60 commercial metal elements,” Prof. Jarvis explained. “In the world of materials it’s the mixing of these different chemical elements that is vital to us: we hardly use pure metals but we do use compounds, alloys and composites.”

    nc
    Nano-catalyst

    A standard laptop might combine more than 20 different metal elements, while putting a spacecraft into orbit typically incorporates upwards of 50 elements, including the rocket, the satellite and all its subsystems, its electronics and the functional materials that go in there.

    “You’ve got those 60 elements and you can mix them in so many different ways,” he added. “The actual number of combinations and ratios of mixing elements is infinite – we’ve only really scratched the surface.”

    tm
    Tellurium metal

    The Metallurgy Europe programme is being organised as a ‘Cluster’ of the EUREKA network. EUREKA is a long-established intergovernmental organisation uniting more than 40 governments, including virtually all the member states of the EU.

    EUREKA Clusters are long-term, strategically significant public-private partnerships, working with Europe’s leading companies to develop competitive-boosting technologies.

    “Metallurgy Europe adopts a bottom-up, multi-sector approach. The topics being tackled come from what industry wants and society needs in the next decade or so.”

    More than 180 industrial partners have signed up, including some of the largest engineering companies in the continent: Airbus Group, BP, Siemens, Daimler, Rolls-Royce, Thales, AvioAero, BAE Systems, Philips, Ruag, Bombardier, Linde Group, Rolex, Richemont, ArcelorMittal, Sandvik, Bruker, Johnson Matthey, Tata Steel, Boston Scientific, ThyssenKrupp, Outokumpu, Hydro Aluminium and Fiat, along with small and medium firms.

    bis
    Semi-metallic bismuth crystal

    Leading research organisations including ESA, the European Synchrotron Radiation Facility, Institut Laue-Langevin, the European Powder Metallurgy Association and the Culham Centre for Fusion Energy are also lending their expertise.

    The projects making up the programme will begin next year, although preparatory work has already begun.

    “The amount of money invested and the size of our support network makes us the largest consortium of its type in metallic materials and advanced manufacturing,” Prof. Jarvis concluded. “It stands us in good stead to be the front runner in this field for quite some time.”

    See the full article here.

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 7:17 pm on September 10, 2014 Permalink | Reply
    Tags: , Material Sciences, ,   

    From SLAC- “Plastics in Motion: Exploring the World of Polymers” 


    SLAC Lab

    September 10, 2014

    Experiment Shows Potential of X-ray Laser to Study Complex, Poorly Understood Materials

    Plastics are made of polymers, which are a challenge for scientists to study. Their chainlike strands of thousands of atoms are tangled up in a spaghetti-like jumble, their motion can be measured at many time scales and they are essentially invisible to some common X-ray study techniques.

    poly
    Illustration of a polystrene molecular chain and Styrofoam cups, which are made of polystyrene. (@iStockphoto/Devonyu, Martin McCarthy)

    gel
    This photograph shows a polymer in a molten, gel-like state. (@iStockphoto/Steve Bjorklund)

    A better understanding of polymers at the molecular scale, particularly as they are cooled from a molten state to a more solid form, could lead to improved manufacturing techniques and the creation of new, customizable materials.

    In an experiment at the Department of Energy’s SLAC National Accelerator Laboratory using SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, a DOE Office of Science User Facility, scientists unraveled the complex behavior of polystyrene, a popular polymer found in packing foams and plastic cups, with a sequence of ultrabright X-ray laser pulses. Their work is detailed in the Aug. 11 edition of Scientific Reports.

    SLAC LCLS
    SLAC LCLS

    They measured natural motion in polystyrene samples heated to a gel-like middle ground between their melting point and solid state. This was the first demonstration that LCLS could be used for studying polymers and a whole range of other complex materials using a technique called X-ray photon correlation spectroscopy (XPCS),

    Hyunjung Kim of Sogang University in Korea, who led this research, said, “It was unknown whether the sample would survive the exposure to the ultrabright X-ray laser pulses. However, the X-ray damage effects on the sample were weaker than expected.”

    SLAC staff scientist Aymeric Robert said, “To see how you get from something that was completely moving to something completely static is very poorly understood. Observations of how polymers move in response to temperature changes and other effects can be compared with theoretical models to predict their behavior.” Robert oversees the experimental station at LCLS that is specially designed for this X-ray technique.

    “LCLS should allow scientists to measure motion in these materials in even more detail than possible using conventional X-ray tools,” he added.

    To study motion in the heated samples, researchers embedded a matrix of nanoscale gold spheres into the polymer. Then, they recorded sequences of up to about 150 X-ray images on different sections of the sample, with the delay between images ranging from as little as seven seconds to as much as 17 minutes.

    The XPCS technique measures successive “speckle” patterns that revealed subtle changes in the position of the gold spheres relative to one another – a measure of motion within the overall sample.

    While many experiments at LCLS capture X-ray data in the instant before samples are destroyed by the intense light, this technique allows some materials to survive the effects of many X-ray pulses, which is useful for studying longer-lived properties spanning from milliseconds to minutes.

    “We showed that we could study the complex dynamics in the polymer sample even at slow time scales,” Kim said. While this experiment proved that LCLS can be used to measure the long-duration motions across the entire sample, Kim said future experiments could vary the arrangement and size of the implanted gold spheres to better gauge motion at the scale of the molecular chains. Also, faster repetition of the X-ray laser pulses could help to study motion on a shorter time scale.

    In addition to Sogang University and SLAC’s LCLS, other participating researchers were from University of California, San Diego, Argonne National Laboratory; DESY lab, The Hamburg Center for Ultrafast Imaging and the University of Siegen, in Germany; Northern Illinois University; University of Massachusetts, Amherst; and Pohang Accelerator Laboratory (PAL) in Korea. The research was supported by the National Research Foundation funded by the Ministry of Science, ICT & Future Planning of Korea, and PAL in Korea, and the Department of Energy Office of Basic Energy Sciences.

    rig
    A view of the X-ray Correlation Spectroscopy experimental station at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser. This station is designed to explore polymers and other hard-to-study materials. (SLAC National Accelerator Laboratory)

    graph
    This image (a) shows the experimental setup for an X-ray photon correlation spectroscopy experiment using polymer samples at SLAC’s Linac Coherent Light Source X-ray laser. (b) This transmission electron microscopy image shows nanoscale gold spheres that were embedded in a molten polymer to help study its motion. (c) This speckle pattern was produced as X-rays struck the polymer sample. A succession of these patterns show the changing positions of the gold spheres in the polymer sample, which provides a measure of the polymer’s motion. (10.1038/srep06017)

    image
    A computerized rendering of the X-ray Correlation Spectroscopy station at SLAC’s Linac Coherent Light Source X-ray laser, which was used to study motion in polymer samples. (SLAC National Accelerator Laboratory)

    See the full article here.

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
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  • richardmitnick 5:03 pm on September 10, 2014 Permalink | Reply
    Tags: , , Material Sciences, ,   

    From LBL: “Advanced Light Source Sets Microscopy Record” 

    Berkeley Logo

    Berkeley Lab

    September 10, 2014
    Lynn Yarris (510) 486-5375

    A record-setting X-ray microscopy experiment may have ushered in a new era for nanoscale imaging. Working at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab), a collaboration of researchers used low energy or “soft” X-rays to image structures only five nanometers in size. This resolution, obtained at Berkeley Lab’s Advanced Light Source (ALS), a DOE Office of Science User Facility, is the highest ever achieved with X-ray microscopy.

    LBL Advanced Light Source
    LBL ALS

    image
    Ptychographic image using soft X-rays of lithium iron phosphate nanocrystal after partial dilithiation. The delithiated region is shown in red.

    Using ptychography, a coherent diffractive imaging technique based on high-performance scanning transmission X-ray microscopy (STXM), the collaboration was able to map the chemical composition of lithium iron phosphate nanocrystals after partial dilithiation. The results yielded important new insights into a material of high interest for electrochemical energy storage.

    “We have developed diffractive imaging methods capable of achieving a spatial resolution that cannot be matched by conventional imaging schemes,” says David Shapiro, a physicist with the ALS. “We are now entering a stage in which our X-ray microscopes are no longer limited by our optics and we can image at nearly the wavelength of our X-ray light.”

    Shapiro is the lead and corresponding author of a paper reporting this research in Nature Photonics. The paper is titled “Chemical composition mapping with nanometer resolution by soft X-ray microscopy.” (See below for a full list of co-authors and their affiliations.)

    ds
    David Shapiro with the STXM instruments at ALS beamline 5.3.2.1. (Photo by Roy Kaltschmidt)

    In ptychography (pronounced tie-cog-raphee), a combination of multiple coherent diffraction measurements is used to obtain 2D or 3D maps of micron-sized objects with high resolution and sensitivity. Because of the sensitivity of soft x-rays to electronic states, ptychography can be used to image chemical phase transformations and the mechanical consequences of those transformations that a material undergoes.

    “Until this work, however, the spatial resolution of ptychographic microscopes did not surpass that of the best conventional systems using X-ray zone plate lenses,” says Howard Padmore, leader of the Experimental Systems Group at the ALS and a co-author of the Nature Photonics paper. “The problem stemmed from the fact that ptychography was primarily developed on hard X-ray sources using simple pinhole optics for illumination. This resulted in a low scattering cross-section and low coherent intensity at the sample, which meant that exposure times had to be extremely long, and that mechanical and illumination stabilities were not good enough for high resolution.”

    Key to the success of Shapiro, and his collaborators were the use of soft X-rays which have wavelengths ranging between 1 to 10 nanometers, and a special algorithm that eliminated the effect of all incoherent background signals. Ptychography measurements were recorded with the STXM instruments at ALS beamline 11.0.2, which uses an undulator x-ray source, and ALS beamline 5.3.2.1, which uses a bending magnet source. A coherent soft X-ray beam would be focused onto a sample and scanned in 40 nanometer increments. Diffraction data would then be recorded on an X-ray CCD (charge-coupled device) that allowed reconstruction of the sample to very high spatial resolution.

    “Throughout the ptychography scans, we maintained the sample and focusing optic in relative alignment using an interferometric feedback system with a precision comparable to the wavelength of the X-ray illumination,” Shapiro says.

    Lithium iron phosphate is widely studied for its use as a cathode material in rechargeable lithium-ion batteries. In using their ptychography technique to map the chemical composition of lithium iron phosphate crystals, Shapiro and his collaborators found a strong correlation between structural defects and chemical phase propagation.

    “Surface cracking in these crystals was expected,” Shapiro says, “but there is no other means of visualizing the correlation of those cracks with chemical composition at these scales. The ability to visualize the coupling of the kinetics of a phase transformation with the mechanical consequences is critical to designing materials with ultimate durability.”

    Shapiro and his colleagues have already begun applying their ptychography technique to the study of catalytic and magnetic films, magnetotactic bacteria, polymer blends and green cements.
    In this soft X-ray ptychography set-up, a 60 nm width outer-zone-plate focuses a coherent soft X-ray beam onto the sample, which is scanned in 40 nm increments to ensure overlap of the probed areas.

    In this soft X-ray ptychography set-up, a 60 nm width outer-zone-plate focuses a coherent soft X-ray beam onto the sample, which is scanned in 40 nm increments to ensure overlap of the probed areas.

    For the chemical mapping of lithium iron phosphate they used the STXM instrument at ALS beamline 5.3.2.1 which required up to 800 milliseconds of exposure to the X-ray beam for each scan. Next year, they anticipate using a new ALS beamline called COSMIC (COherent Scattering and MICroscopy), which will feature a high brightness undulator x-ray source coupled to new high-frame-rate CCD sensors that will cut beam exposure times to only a few milliseconds and provide spatial resolution at the wavelength of the radiation.

    image2
    In this soft X-ray ptychography set-up, a 60 nm width outer-zone-plate focuses a coherent soft X-ray beam onto the sample, which is scanned in 40 nm increments to ensure overlap of the probed areas. – See more at: http://newscenter.lbl.gov/2014/09/10/advanced-light-source-sets-microscopy-record/#sthash.6DLMbCxp.dpuf

    “If visible light microscopes could only achieve a resolution that was 50 times the wavelength of visible light, we would not be able to see most single celled organisms,” Shapiro says. “Where would the life sciences be with such a limitation? We are now approaching the point where we will have X-ray microscopes of comparable quality to today’s visible light instruments for the study of nanomaterials.”

    Co-authoring the Nature Photonics paper in addition to Shapiro and Padmore were Young-Sang Yu, Tolek Tyliszczak, Jordi Cabana, Rich Celestre, Weilun Chao, David Kilcoyne, Stefano Marchesini, Tony Warwick and Lee Yang of Berkeley Lab; Konstantin Kaznatcheev of Brookhaven National Laboratory; Shirley Meng of the University of San Diego; and Filipe Maia of Uppsala University in Sweden.

    This research was primarily supported by the DOE Office of Science.

    See the full article here.

    A U.S. Department of Energy National Laboratory Operated by the University of California

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  • richardmitnick 12:59 pm on September 9, 2014 Permalink | Reply
    Tags: , Material Sciences, , ,   

    From SLAC: “Buckyballs and Diamondoids Join Forces in Tiny Electronic Gadget” 


    SLAC Lab

    September 9, 2014
    Press Office Contact: Andrew Gordon, agordon@slac.stanford.edu, (650) 926-2282

    Scientists Craft Two Exotic Forms of Carbon into a Molecule for Steering Electron Flow

    Scientists have married two unconventional forms of carbon – one shaped like a soccer ball, the other a tiny diamond – to make a molecule that conducts electricity in only one direction. This tiny electronic component, known as a rectifier, could play a key role in shrinking chip components down to the size of molecules to enable faster, more powerful devices.

    dd
    An international team led by researchers at SLAC National Accelerator Laboratory and Stanford University joined two offbeat carbon molecules – diamondoids, the square cages at left, and buckyballs, the soccer-ball shapes at right – to create “buckydiamondoids,” center. These hybrid molecules function as rectifiers, conducting electrons in only one direction, and could help pave the way to molecular electronic devices. (Manoharan Lab/Stanford University)

    “We wanted to see what new, emergent properties might come out when you put these two ingredients together to create a ‘buckydiamondoid,’” said Hari Manoharan of the Stanford Institute for Materials and Energy Sciences (SIMES) at the Department of Energy’s SLAC National Accelerator Laboratory. “What we got was a basically a one-way valve for conducting electricity – clearly more than the sum of its parts.”

    The research team, which included scientists from Stanford University, Belgium, Germany and Ukraine, reported its results September 9, 2014, in Nature Communications.

    Two Offbeat Carbon Characters Meet Up

    Many electronic circuits have three basic components: a material that conducts electrons; rectifiers, which commonly take the form of diodes, to steer that flow in a single direction; and transistors to switch the flow on and off. Scientists combined two offbeat ingredients – buckyballs and diamondoids – to create the new diode-like component.

    Buckyballs – short for buckminsterfullerenes – are hollow carbon spheres whose 1985 discovery earned three scientists a Nobel Prize in chemistry. Diamondoids are tiny carbon cages bonded together as they are in diamonds, but weighing less than a billionth of a billionth of a carat. Both are subjects of a lot of research aimed at understanding their properties and finding ways to use them.

    In 2007, a team led by researchers from SLAC and Stanford discovered that a single layer of diamondoids on a metal surface can efficiently emit a beam of electrons. Manoharan and his colleagues wondered: What would happen if they paired an electron-emitting diamondoid with another molecule that likes to grab electrons? Buckyballs are just that sort of electron-grabbing molecule.

    A Very Small Valve for Channeling Electron Flow

    For this study, diamondoids were produced in the SLAC laboratory of SIMES researchers Jeremy Dahl and Robert Carlson, who are world experts in extracting the tiny diamonds from petroleum. They were then shipped to Germany, where chemists at Justus-Liebig University figured out how to attach them to buckyballs.

    The resulting buckydiamondoids, which are just a few nanometers long, were tested in SIMES laboratories at Stanford. A team led by graduate student Jason Randel and postdoctoral researcher Francis Niestemski used a scanning tunneling microscope to make images of the hybrid molecules and measure their electronic behavior. They discovered the hybrid is an excellent rectifier: The electrical current flowing through the molecule was up to 50 times stronger in one direction, from electron-spitting diamondoid to electron-catching buckyball, than in the opposite direction. This is something neither component can do on its own.

    ball
    An image made with a scanning tunneling microscope shows hybrid buckydiamondoid molecules on a gold surface. The buckyball end of each molecule is attached to the surface, with the diamondoid end sticking up; both are clearly visible. The area shown here is 5 nanometers on a side. (H. Manoharan et al, Nature Communications)

    image
    Illustration of a buckydiamondoid molecule under a scanning tunneling microscope (STM). The sharp metallic tip of the STM ends in a single atom; as it scans over a sample, electrons tunnel from the tip into the sample. In this study the STM made images of the buckydiamondoids and probed their electronic properties. (SLAC National Accelerator Laboratory)

    While this is not the first molecular rectifier ever invented, it’s the first one made from just carbon and hydrogen, a simplicity researchers find appealing, said Manoharan, who is an associate professor of physics at Stanford. The next step, he said, is to see if transistors can be constructed from the same basic ingredients.

    “Buckyballs are easy to make – they can be isolated from soot – and the type of diamondoid we used here, which consists of two tiny cages, can be purchased commercially,” he said. “And now that our colleagues in Germany have figured out how to bind them together, others can follow the recipe. So while our research was aimed at gaining fundamental insights about a novel hybrid molecule, it could lead to advances that help make molecular electronics a reality.”

    Other research collaborators came from the Catholic University of Louvain in Belgium and Kiev Polytechnic Institute in Ukraine. The primary funding for the work came from the U.S. Department of Energy Office of Science.

    See the full article here.

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
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