materials research – Lightsources.org

Cellulose-based actuators can be programmed and repair themselves

2022/11/212022/11/22

Smart gifts will soon unwrap themselves

With the help of the high-brilliance X-ray source PETRA III, a German-Swedish research group has developed a new cellulose polymer material that can be specifically animated to move by moisture, making it an ideal base material for programmable actuators. In addition, the composite material is also very resistant to stretching and able to repair itself, as the group reports in the scientific journal “Advanced Functional Materials”. The mechanism of this self-healing in particular was investigated at PETRA III.

n nature, fascinating functions and mechanisms have prevailed over millions of years of evolution. In bionics research, scientists try to copy and reproduce these efficient methods from nature. For example, in sensors or bionic actuators, active elements that – controlled by a signal – can switch or move something. Modern actuators should be programmably stimulable, very robust and able to cope with a wide range of working conditions.

The research team with members from the Royal Institute of Technology Stockholm (KTH), DESY and the Helmholtz Centre for Heavy Ion Research has now produced a thin film of cellulose nanofibres with two types of polymers, following the example of biological tissue. To do this, they mixed polyvinyl alcohol (PVA) and polystyrene sulfonate (PSS) with the cellulose fibrils and poured the solution onto a glass plate. When it dried out, a circular film was formed in which a tight network of chemical and physical bonds formed. “It is the polystyrene sulphonate in particular that makes the film extremely stretchable and tough,” says DESY scientist Qing Chen, first author of the study. “This ingredient of the solution can be broadened by mixing food colouring agents, thus making it more colourful and diverse.”

Pieces up to several centimetres in size can be cut out of this film, which bend when exposed to moisture. “In principle, we can make an active wrapping paper out of the material,” says Stephan Roth (DESY and KTH), head of the PETRA III beamline P03 and co-author of the study, “you just have to spray some moisture on it, and it unwraps itself.”

Read more on the DESY website

Image: The cellulose polymer actuators can be used for a variety of purposes.

Credit: DESY, Qing Chen

Artificial intelligence deciphers detector “clouds” to accelerate materials research

2022/11/072022/11/22

A machine learning algorithm automatically extracts information to speed up – and extend – the study of materials with X-ray pulse pairs.

X-rays can be used like a superfast, atomic-resolution camera, and if researchers shoot a pair of X-ray pulses just moments apart, they get atomic-resolution snapshots of a system at two points in time. Comparing these snapshots shows how a material fluctuates within a tiny fraction of a second, which could help scientists design future generations of super-fast computers, communications, and other technologies.

Resolving the information in these X-ray snapshots, however, is difficult and time intensive, so Joshua Turner, a lead scientist at the Department of Energy’s SLAC National Accelerator Center and Stanford University, and ten other researchers turned to artificial intelligence to automate the process. Their machine learning-aided method, published October 17 in Structural Dynamics, accelerates this X-ray probing technique, and extends it to previously inaccessible materials.

“The most exciting thing to me is that we can now access a different range of measurements, which we couldn’t before,” Turner said.

Handling the blob

When studying materials using this two-pulse technique, the X-rays scatter off a material and are usually detected one photon at a time. A detector measures these scattered photons, which are used to produce a speckle pattern – a blotchy image that represents the precise configuration of the sample at one instant in time. Researchers compare the speckle patterns from each pair of pulses to calculate fluctuations in the sample.

“However, every photon creates an explosion of electrical charge on the detector,” Turner said. “If there are too many photons, these charge clouds merge together to create an unrecognizable blob.” This cloud of noise means the researchers must collect tons of scattering data to yield a clear understanding of the speckle pattern.

“You need a lot of data to work out what’s happening in the system,” said Sathya Chitturi, a Ph.D. student at Stanford University who led this work. He is advised by Turner and coauthor Mike Dunne, director of the Linac Coherent Light Source (LCLS) X-ray laser at SLAC.

Read more on the SLAC website

Image: A speckle pattern typical of the sort seen at LCLS’s detectors

Credit: Courtesy Joshua Turner

Unraveling the structural transformation of Li-rich materials in lithium-batteries

2022/10/052022/10/19

Lithium-Ion Batteries (LIBs) are essentials in everyday life in mobile applications as well as in hybrid/electric mobility. The extraordinary market success of this technology is forcing hard the need of LIBs with improved energy density, environmental compatibility and safety, making necessary to push this technology beyond the current state of the art. In this framework, Co-poor Lithium Rich Layered Oxides (LRLOs) are the most strategic alternative to current Co-rich layered oxide positive electrode materials thanks to the excellent combination of large specific capacity (>250 mAhg^-1), high energy density (up to 900 WhKg^-1), small costs and improved environmental benignity. The excellent performance of LRLOs derives from the peculiar combination of redox processes originated from the transition metals and the oxygen anions sublattice. The practical use of LRLOs is hindered by several drawbacks, such as voltage decay, capacity fading, and an irreversible capacity lost in the first cycle. These issues are related to structural rearrangements in the lattice upon cycling.

In this work, we demonstrate a new family of LRLOs with general formula Li_1.2+xMn_0.54Ni_0.13Co_x-yAl_0.03O₂ (0.03 ≤ x ≤ 0.08 and 0.03 ≤ y ≤ 0.05), obtained from the replacement of cobalt with lithium and aluminum and we highlight how the balancing of the metal blend can lead to improvements of the Coulombic efficiency in the first cycle, a better capacity retention and reduced voltage decay. To shed light on the complex crystal-chemistry of this class of LRLOs we studied the Co-poorest member of this homologue material series, namely Li_1.28Mn_0.54Ni_0.13Co_0.02Al_0.03O₂, in order to prove the structural evolution occurring upon charge/discharge in lithium cell. To these aims, electrodes have been recovered during the first cycle, the second cycle and after ten cycles of charge/discharge by de-assembling lithium cells into an Ar-filled glove box. These post mortem materials have been sealed in borosilicate capillary tubes (see Fig. 1a) and studied ex situ by X-ray powder diffraction at the MCX beamline.

Read more on the Elettra website

Image: Fig. 1b shows the potential curves vs time for the first two cycles and highlights the points, marked with A, B, C and so on, where the charge or discharge step was stopped and the materials recovered for analysis. According to the diffraction data (Fig. 1c), structural alterations of Li_1.28Mn_0.54Ni_0.13Co_0.02Al_0.03O₂ start with a fast broadening and a shift of the peaks suggesting a smooth lattice modification. When the cell reaches 4.8V vs Li⁺, a second phase can be identified. In the discharge process opposite structural transformations occur.

Three research facilities reveal magnetic crossover

2022/09/122022/09/21

Spins tick-tock like a grandfather clock and then stop. Thanks to complementary experiments at the Swiss Muon Source SµS, Swiss Spallation Neutron Source SINQ and the Swiss Light Source SLS, researchers led by the University of Geneva have discovered this coveted characteristic, known as magnetic crossover, hidden within the magnetic landscape of an exotic layered material. Magnetic crossover means tuneability and with it promise for spin-based electronics.

A two-dimensional layered material that is magnetic and a small band gap semiconductor? For the electronics of tomorrow, you could say that Chromium Sulfide Bromide (CrSBr) has it all. “Any new magnetic features that you can find in the material can be useful from a practical point of view”, says Zurab Guguchia, scientist in muon spin spectroscopy at PSI. Together with clues from two other of PSI’s large research facilities, this technique would reveal the highly sought-after trait of magnetic crossover in this exciting new material.

The researchers discovered that as CrSBr is cooled, magnetic fluctuations in the material – where the spins tick-tock back and forth like a grandfather clock – slow down and then freeze. This process is known as magnetic crossover. Interestingly, this is a gradual ‘crossover’ from one state to another, rather than a sharp transition that occurs at one temperature. And it is this characteristic that makes it such an appealing characteristic for spin based electronics devices, as Guguchia explains:

“We believe that this dynamic magnetic behaviour comes from competing interactions and frustrations that exist between the layers in the material. This means, with an external parameter we could tune it: push it in either direction. You couldn’t do this if it was just in one boring state.”

Read more on the PSI website

Image: To discover the hidden order within CrSBr’s magnetic structure, researchers needed complementary evidence from three different facilities: the Swiss Muon Source, the Swiss Spallation Neutron Source and the Swiss Light Source. With these techniques, they could reveal that spin fluctuations dwindled and then froze at 40 degrees Kelvin

Credit: Paul Scherrer Institute / Mahir Dzambegovic

Great minds think alike!

2021/12/202021/12/20

Marion Flatken from BESSY II & Luisa Napolitano from Elettra give advice to those at the start of their careers

Our #LightSourceSelfies campaign features staff and users from 25 light sources across the world. We invited them all to answer a specific set of questions so we could share their insights and advice via this video campaign. Today’s montage features Marion Flatken from BESSY II, in Germany, and Luisa Napolitano from Elettra, in Italy. Both scientists offered the same advice to those starting out on their scientific journeys: “Be curious and stay curious”. Light source experiments can be very challenging and the tough days can lead to demotivation and self-doubts. In these times, it is good to seek out support from colleagues, all of whom will have experienced days like this. Even if you think you can’t succeed with your research goals, try because it is amazing what can be achieved through hard work, tenacity and collaboration.

Unexpected Transformations Reinforce Roman Concrete

2021/12/072022/01/13

Researchers used the Advanced Light Source (ALS) to study binding phases in Roman architectural concrete, revealing reactions and profound transformations that contribute to the material’s long-term cohesion and durability.

The findings add to our growing understanding of cementing processes in Roman concretes, informing resilient materials of the future.

Marie Jackson, a research associate professor at the University of Utah, has devoted much of her career to understanding the scientific mysteries underlying the exceptional durability of Roman concretes. The ALS has been essential to her and her colleagues’ studies, helping to reveal the chemical and microstructural evolution of the materials.

Concrete is made of rock aggregates and a binder. Modern concretes typically use Portland cement—made by burning a mixture of limestone and clay at high temperature—as binder. Roman concretes, in contrast, consist of coarse volcanic rock (or brick) aggregate bound with mortar made from hydrated lime and reactive tephra—the particles ejected from explosive volcanic eruptions.

In this study, Jackson, along with collaborators Admir Masic and Linda Seymour of the Massachusetts Institute of Technology and Nobumichi Tamura of the ALS, examined mortar samples from the Tomb of Caecilia Metella in Rome. The team hoped that the 2,050-year-old monument would provide insights into how Roman builders’ selections of reactive volcanic rock influenced the material characteristics of the very robust concrete.

Read more on the ALS website

Image: The Tomb of Caecilia Metella on the Via Appia Antica in Rome. The edifice is one of the most refined concrete and dimension stone structures of the latest Roman Republican era.

Credit: Emmanuel Brunner

Photon Factory Highlights 2020

2021/12/032021/12/09

The research highlights based on the Photon Factory (PF) users’ program during fiscal 2020 (April 2020 – March 2021), is now available on the web.

The sections covered include:

Materials Science

Chemical Science

Earth & Planetary Science

Life Science

Instrumentation & Techniques

Accelerator

Access these highlights via the Photon Factory website

Image: Highlights 2020 cover

Credit: Photon Factory, KEK

One year of ESRF-EBS

2021/08/252021/08/26

One year ago, the ESRF switched on its Extremely Brilliant Source (EBS), a revolutionary new high-energy, fourth-generation synchrotron light source, a €150m project over 2015-2022 funded by ESRF’s 22 partner countries.

An accelerator physics dream saw the light with the launch of the world’s brightest synchrotron source, ESRF-EBS, inspiring many constructions and upgrades of synchrotron light sources around the world. Thanks to its enhanced performances, EBS has opened new vistas for X-rays science, enabling scientists to bring X-ray science into research domains and applications that could not have been imagined a few years ago, and providing invaluable new insight into the microscopic and atomic structure of living matter and materials in all their complexity.

Today, the ESRF celebrates one year of user operation of EBS and one year of exciting new science. “Europe can be proud of this masterpiece of state-of-the-art technology and scientific vision,” says Helmut Dosch, Chair of the ESRF Council.

Read more on the ESRF website

Image: Exterior view of the ESRF-EBS in Grenoble, France

Credit: ESRF

Grain-scale deformation of a high entropy alloy

2021/08/112021/08/26

New research that exploited the unique strengths of the FAST beamline produced some of the first measurements of individual grain deformation in high entropy alloys. This data can help form accurate predictions of damage and failure processes in these emerging materials, critical for understanding their performance in real-world applications.

Grains and strains | A subset of the thousands of indexed grains are shown, along with their axial elastic strains (top) and maximum resolved sheer stress (bottom), at 4 positions indicated on the stress-strain curve. This microscopic detail is only available via high-energy x-ray techniques.

What is the discovery?

Conventional alloys are made primarily of one metal element, with a small substitution of other atoms to tune the properties (for example, 7.5% Cu and 92.5% Ag produces sterling silver). Recently, new types of high entropy alloys (HEAs) have been discovered, which are made by mixing many different metallic elements in nearly-equal proportions. HEAs can exhibit remarkably different properties from conventional alloys. In a new paper, a team lead by Jerard Gordon from the University of Michigan reports a high-energy x-ray study of the HEA made from mixing equal amounts of Co, Cr, Fe, Mn, and Ni. The team was able to use far-field high-energy diffraction microscopy (ff-HEDM) to understand the microscopic response of thousands of individual crystal grains in their sample when it is deformed under load. They were also able to compare the results with detailed crystal-plasticity models.

Read more on the CHESS website

Image: Grains and strains | A subset of the thousands of indexed grains are shown, along with their axial elastic strains (top) and maximum resolved sheer stress (bottom), at 4 positions indicated on the stress-strain curve. This microscopic detail is only available via high-energy x-ray techniques.

Scientists glimpse signs of a puzzling state of matter in a superconductor

2021/04/212021/04/27

Known as “pair-density waves,” it may be key to understanding how superconductivity can exist at relatively high temperatures.

Unconventional superconductors contain a number of exotic phases of matter that are thought to play a role, for better or worse, in their ability to conduct electricity with 100% efficiency at much higher temperatures than scientists had thought possible – although still far short of the temperatures that would allow their wide deployment in perfectly efficient power lines, maglev trains and so on.

Now scientists at the Department of Energy’s SLAC National Accelerator Laboratory have glimpsed the signature of one of those phases, known as pair-density waves or PDW, and confirmed that it’s intertwined with another phase known as charge density wave (CDW) stripes – wavelike patterns of higher and lower electron density in the material.

Observing and understanding PDW and its correlations with other phases may be essential for understanding how superconductivity emerges in these materials, allowing electrons to pair up and travel with no resistance, said Jun-Sik Lee, a SLAC staff scientist who led the research at the lab’s Stanford Synchrotron Radiation Lightsource (SSRL).

Read more on the SLAC website

Image: SLAC scientists used an improved X-ray technique to explore exotic states of matter in an unconventional superconductor that conducts electricity with 100% efficiency at relatively high temperatures. They glimpsed the signature of a state known as pair density waves (PDW), and confirmed that it intertwines with another phase known as charge density wave (CDW) stripes – wavelike patterns of higher and lower electron density in the material. CDWs, in turn, are created when spin density waves (SDWs) emerge and intertwine.

Credit: Jun-Sik Lee/SLAC National Accelerator Laboratory

AI Agent Helps Identify Material Properties Faster

2021/04/202021/04/21

High-throughput X-ray diffraction measurements generate huge amounts of data. The agent renders them usable more quickly.

Artificial intelligence (AI) can analyse large amounts of data, such as those generated when analysing the properties of potential new materials, faster than humans. However, such systems often tend to make definitive decisions even in the face of uncertainty; they overestimate themselves. An international research team has stopped AI from doing this: the researchers have refined an algorithm so that it works together with humans and supports decision-making processes. As a result, promising new materials can be identified more quickly.

A team headed by Dr. Phillip M. Maffettone (currently at National Synchrotron Light Source II in Upton, USA) and Professor Andrew Cooper from the Department of Chemistry and Materials Innovation Factory at the University of Liverpool joined forces with the Bochum-based group headed by Lars Banko and Professor Alfred Ludwig from the Chair of Materials Discovery and Interfaces and Yury Lysogorskiy from the Interdisciplinary Centre for Advanced Materials Simulation. The international team published their report in the journal Nature Computational Science from 19 April 2021.

Read more on the BNL website

Image: Daniel Olds (left) and Phillip M. Maffettone working at the beamline.

Credit: BNL

New insights into the photochemical activity of titanium dioxide

2021/04/092021/04/15

Not so many compounds are as important to industry and medicine today as titanium dioxide (TiO2). The electronic structure of transition metal oxides is an important factor determining the chemical and optical properties of materials. Specifically for metal-oxide structures, the crystal-field interaction determines the shape and occupancy of electronic orbitals. Consequently, the crystal-field splitting and resulting unoccupied state populations can be foreseen as modeling factors of the photochemical activity. The research on titanium dioxide inaugurated the presence of IFJ PAN scientists in research programs carried out at the SOLARIS synchrotron. The measurements, co-financed by the National Science Center, were carried out at the XAS beamline.

In many chemical reactions, TiO₂ appears as a catalyst. As a pigment, it occurs in plastics, paints, and cosmetics, while in medical implants, it guarantees their high biocompatibility. A group of scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Krakow, led by Dr. Jakub Szlachetka, engaged in research on the oxidation processes of the outer layers of titanium samples and related changes in the electronic structure of this material. Scientists from the IFJ PAN conducted their latest measurements, co-financed by the National Science Center, at the XAS beamline. They analyzed how X-rays are absorbed by the surface layers of titanium samples previously produced at the Institute under carefully controlled conditions.

Read more on the SOLARIS website

Researchers capture how materials break apart following an extreme shock

2021/02/232021/03/11

Understanding how materials deform and catastrophically fail when impacted by a powerful shock is crucial in a wide range of fields, including astrophysics, materials science and aerospace engineering. But until recently, the role of voids, or tiny pores, in such a rapid process could not be determined, requiring measurements to be taken at millionths of a billionth of a second.

Now an international research team has used ultrabright X-rays to make the first observations of how these voids evolve and contribute to damage in copper following impact by an extreme shock. The team, including scientists from the University of Miami, the Department of Energy’s SLAC National Accelerator Laboratory and Argonne National Laboratory, Imperial College London and the universities of Oxford and York published their results in Science Advances.

“Whether these materials are in a satellite hit by a micrometeorite, a spacecraft entering the atmosphere at hypersonic speed or a jet engine exploding, they have to fully absorb all that energy without catastrophically failing,” says lead author James Coakley, an assistant professor of mechanical and aerospace engineering at the University of Miami. “We’re trying to understand what happens in a material during this type of extremely rapid failure. This experiment is the first round of attempting to do that, by looking at how the material compresses and expands during deformation before it eventually breaks apart.”

Investigating 3D-printed structures in real time

2020/07/222020/08/03

Scientists used ultrabright x-rays to watch the developing structure of a 3D-printed part evolve during the printing process.

A team of scientists working at the National Synchrotron Light Source II (NSLS-II) at the U.S. Department of Energy’s (DOE’s) Brookhaven National Laboratory has designed an apparatus that can take simultaneous temperature and x-ray scattering measurements of a 3D printing process in real time, and have used it to gather information that may improve finished 3D products made from a large variety of plastics. This study could broaden the scope of the printing process in the manufacturing industry and is also an important step forward for Brookhaven Lab and Stony Brook University’s collaborative advanced manufacturing program.

The researchers were studying a 3D printing method called fused filament fabrication, now better known as material extrusion. In material extrusion, filaments of a thermoplastic—a polymer that softens when heated and hardens when cooled—are melted and deposited in many thin layers to build a finished structure. This approach is often called “additive” manufacturing because the layers add up to produce the final product.

Read more on the NSLS-II website
Image: The photo shows the research team, (from front to back) Yu-Chung Lin, Miriam Rafailovich, Aniket Raut, Guillaume Freychet, Mikhail Zhernenkov, and Yuval Shmueli (not pictured), placing the 3D printer into the chamber of the Soft Matter Interfaces (SMI) beamline at Brookhaven Lab’s National Synchrotron Light Source II (NSLS-II).
Note: this photo was taken in March 2020, prior to current COVID-19 social distancing guidelines.

How new materials increase the efficiency of direct ethanol fuel cells

2020/05/042020/07/02

A group from Brazil and an HZB team have investigated a novel composite membrane for ethanol fuel cells. It consists of the polymer Nafion, in which nanoparticles of a titanium compound are embedded by the rarely explored melt extrusion process. At BESSY II they were able to observe in detail, how the nanoparticles in the Nafion matrix are distributed and how they contribute to increase proton conductivity.

Ethanol has five times higher volumetric energy density (6.7 kWh/L) than hydrogen (1.3 kWh/L) and can be used safely in fuel cells for power generation. In Brazil in particular there is great interest in better fuel cells for ethanol as all the country distributes low-cost ethanol produced in a renewable way from sugar cane. Theoretically, the efficiency of an ethanol fuel cell should be 96 percent, but in practice at the highest power density it is only 30 percent, due to a variety of reasons. So there is great room for improvements.

Nafion with nanoparticles

A team led by Dr. Bruno Matos from the Brazilian research institute IPEN is therefore investigating novel composite membranes for direct ethanol fuel cells. A promising solution is tailoring new polymer-based composite electrolyte materials to replace the state-of-the-art polymer electrolyte such as Nafion. Matos and his team use melt extrusion process to produce composite membranes based on Nafion with additional titanate nanoparticles, which have been functionalized with sulfonic acid groups.

Read more on BESSY II (at HZB) website

Image: The material consists of Nafion with embedded nanoparticles.