Secrets of skyrmions revealed

Why skyrmions could have a lot in common with glass and high-temperature superconductors

Spawned by the spins of electrons in magnetic materials, these tiny whirlpools behave like independent particles and could be the future of computing. Experiments with SLAC’s X-ray laser are revealing their secrets.

Scientists have known for a long time that magnetism is created by the spins of electrons lining up in certain ways. But about a decade ago, they discovered another astonishing layer of complexity in magnetic materials: Under the right conditions, these spins can form little vortexes or whirlpools that act like particles and move around independently of the atoms that spawned them.

The tiny whirlpools are called skyrmions, named after Tony Skyrme, the British physicist who predicted their existence in 1962. Their small size and sturdy nature – like knots that are hard to undo – have given rise to a rapidly expanding field devoted to understanding them better and exploiting their strange qualities.

“These objects represent some of the most sophisticated forms of magnetic order that we know about,” said Josh Turner, a staff scientist at the Department of Energy’s SLAC National Accelerator Laboratory and principal investigator with the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC.

Read more on the SLAC website

Images: Top: Images based on simulations show how three phases of matter, including skyrmions – tiny whirlpools created by the spins of electrons – can form in certain magnetic materials. They are stripes of electron spin (left); hexagonal lattices (right); and an in-between phase (center) that’s a mixture of the two. In this middle, glass-like state, skyrmions move very slowly, like cars in a traffic jam – one of several discoveries made in recent studies by scientists at SLAC, Stanford, Berkeley Lab and UC San Diego. Bottom: Patterns formed in a detector during experiments that explored fundamentals of skyrmion behavior at SLAC’s Linac Coherent Light Source X-ray free-electron laser.

Credit: Esposito et al., Applied Physics Letters, 2020

X-ray insights may enable better plastics production

Analysis helps to understand fragmentation of catalyst particles in ethylene polymerisation

An X-ray study at DESY is pointing the way towards a better understanding of plastics production. A team led by Utrecht University investigated so-called Ziegler-type catalysts, the workhorses in the world’s polyethylene and polypropylene production, at DESY’s X-ray source PETRA III. As the scientists report in the journal JACS Au, the catalyst microparticles fragment into an astonishing variety of smaller particles during polymer production. The results allow for a better finetuning of desired polymer properties and may even help to further increase polymer yield.

Polyolefins, such as polyethylene (PE) and polypropylene (PP), play an important role in everyday life. Applications range from food packaging to increase the lifetime of the product to the sterile packing of medical equipment to the insulation of electrical cables. To prepare tailored polyolefins on demand, a versatile class of catalyst materials, such as the Ziegler-type catalysts, are used that consist of very small particles containing various metals such as titanium.

The catalyst particles have typical sizes of only a few tens of micrometres (thousandths of a millimetre), that is, less than the thickness of a human hair. Thanks to these catalysts, polyethylene can be produced at ambient pressure and temperature and with enhanced material characteristics. “Polyolefin research today focusses on specifically tailoring polymer properties to the demands of customers, and this is where insights about the polymerisation process such as the ones obtained in this study are crucial,” explains Koen Bossers from Utrecht University, first author of the study.

Read more on the DESY website

Image: 434 particles were imaged simultaneously with a resolution of 74 nm and identified and characterised individually with respect to their geometrical properties and fragmentation behaviour. The displayed rendering shows a virtual cut through the tomographic data set where each identified particle is color-coded for better visualisation. Most particles are about 5-6 microns in diameter. The data has further been segmented into regions of similar electron density to separate polymer from catalyst fragments within each particle; these regions are displayed in blue, green, orange, and red and visualised via the virtual cut though the 3-D representation of the catalyst particles. This segmentation allowed for a detailed analysis of the fragmentation behaviour of each particle

Credit: Utrecht University, Roozbeh Valadian

Using science to make the best chocolate yet

Scientists used synchrotron technology to show a key ingredient can create the ideal chocolate structure and could revolutionize the chocolate industry.

Structure is key when it comes creating the best quality of chocolate. An ideal internal structure will be smooth and continuous, not crumbly, and result in glossy, delicious, melt-in-your-mouth decadence. However, this sweet bliss is not easy to achieve.

Researchers from the University of Guelph had their first look at the detailed structure of dark chocolate using the Canadian Light Source (CLS) at the University of Saskatchewan. Their results were published today in Nature Communications.

“One of the major problems in chocolate making is tempering,” said Alejandro Marangoni, a professor at the University of Guelph and Canada Research Chair in Food, Health and Aging. “Very much like when you temper steel, you have to achieve a certain crystalline structure in the cocoa butter.”

Skilled chocolate makers use specialized tools and training to manipulate cocoa butter for gourmet chocolate. However, Marangoni wondered if adding a special ingredient to chocolate could drive the formation of the correct crystal structure without the complex cooling and mixing procedures typically used by chocolatiers during tempering.

Read more on the Canadian Light Source website

Image: Dr. Saeed Ghazani tempering chocolate. Dept. Food Science University of Guelph.

A new approach creates an exceptional single-atom catalyst for water splitting

Anchoring individual iridium atoms on the surface of a catalytic particle boosted its performance in carrying out a reaction that’s been a bottleneck for sustainable energy production.

A new way of anchoring individual iridium atoms to the surface of a catalyst increased its efficiency in splitting water molecules to record levels, scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University reported today.

It was the first time this approach had been applied to the oxygen evolution reaction, or OER ­–part of a process called electrolysis that uses electricity to split water into hydrogen and oxygen. If powered by renewable energy sources, electrolysis could produce fuels and chemical feedstocks more sustainably and reduce the use of fossil fuels. But the sluggish pace of OER has been a bottleneck to improving its efficiency so it can compete in the open market.

The results of this study could ease the bottleneck and open new avenues to observing and understanding how these single-atom catalytic centers operate under realistic working conditions, the research team said.

They published their results today in the Proceedings of the National Academy of Sciences.

Read more on the SLAC website

Image: An illustration depicts a new system developed at SLAC and Stanford that anchors individual iridium atoms to the surface of a catalyst, increasing its efficiency at splitting water to record levels. The eight-sided support structures, shaded in blue, each contain a single iridium atom (large blue spheres). The iridium atoms grab passing water molecules (floating above and to the left of them), and encourage them to react with each other, releasing oxygen molecules (above and to the right). This reaction, known as the oxygen evolution reaction or OER, plays a key role in producing sustainable fuels and chemicals.

Credit: Greg Stewart/SLAC National Accelerator Laboratory

One year of ESRF-EBS

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

Diamond helps discover microscopic metallic particles in the brain

A UK-led international team of researchers has discovered elemental metallic copper and iron in the human brain for the first time. The team, comprised of scientists from Keele University and the University of Warwick in collaboration with the University of Texas at San Antonio (UTSA), used Diamond, and the Advanced Light Source located in California (USA) to identify elemental metallic copper and magnetic elemental iron within the amyloid plaques, chemical forms of copper and iron previously undocumented in human biology.

The study, published in Science Advances and funded by the UKRI’s Engineering and Physical Sciences Research Council, looked at amyloid plaques isolated from the brain tissue of deceased Alzheimer’s patients. Amyloid plaques, a hallmark feature of Alzheimer’s disease, act as a site of disrupted metal chemistry in the Alzheimer’s brain, and are believed by many to be integral to disease progression.

Read more on Diamond website

Image: X-ray microscope images and X-ray absorption spectra obtained from two Alzheimer’s disease plaque cores, measured at Diamond’s beamline I08. Image: Science Advances.

Credit: Science Advances.

X-rays get a grip on why erucamide slips

X-Ray Reflectivity measurements offer insights into a slippery industrial additive

Slip additives have a wide range of industrial uses, finding their way into everything from lubricants to healthcare products. Fatty acid amides have been used as slip additives since the 1960s, and erucamide is widely used in polymer manufacturing. Research into erucamide migration and distribution and its nanomechanical properties has shown that the assembly and performance of the slip-additive surface depend on concentration and application method, as well as the substrate surface chemistry. However, questions remain regarding the nanostructure of organised erucamide surface layers, including the molecular orientation of the outermost erucamide layer. In work recently published in the Journal of Colloid and Interface Science, a team of researchers from the University of Bristol and Procter & Gamble used a combination of techniques to investigate the erucamide nanostructure formed in a model system. Their findings will allow the use of rigorous scientific methods in real-world scenarios. 

Essential erucamide

Manufacturers use slip additives to modify the surface structure of a wide range of materials, reducing friction without compromising the material’s other properties (e.g. modulus). Slip additives are included in everything from food packaging and textiles, dyes and lubricants, to hygiene products such as nappies.

Read on the Diamond website

Image:Multiscale characterisation of polypropylene (PP) fibre vs polypropylene fibre + 1.5 % erucamide: (A) Optical microscopy, (B) Scanning Electron Microscopy, (C) Atomic Force Microscopy (height image)

Rotation and axial motion system IV (RAMS IV) load frame

In spring 2021, the fourth generation of Rotation and Axial Motion System (RAMS IV) load frame was commissioned with X-rays at the Structural Materials Beamline (SMB)

WHAT DID THE SCIENTISTS DO?

The main objectives of commissioning were to enable communication between the existing control system of the beamline (SPEC) and the new control system of RAMS IV (Aerotech), and to synchronize triggering of X-ray detectors with positions of the rotation stages on RAMS IV. To this end, a number of new scripts were written and tested for both SPEC and Aerotech for executing commands, exchanging experimental parameters, interlocking and “handshaking” between the two systems. During the last few days of commissioning, a series of X-ray measurements were performed on a sample mounted on RAMS IV to test the main functionalities of the new load frame.

WHAT ARE THE BROADER IMPACTS OF THIS WORK?

The RAMS load frame series collectively form the gold standard for high-impact, precision in-situ X-ray mechanical testing at high-energy synchrotrons. The longstanding collaboration between Air Force Research Laboratory (AFRL) and Pulseray Inc. has delivered a new design and controls system.

Two RAMS IV frames were built: (1) a CHESS design for in-situ X-ray studies, and (2) an AFRL design for ex-situ studies. The AFRL machine can be used for ex-situ proof-of-concept, preparatory loading, or longer mechanical loading tests that can complement and inform work that is done in situ on the CHESS machine.

RAMS IV is optimized for simultaneous tension, torsion, and fatigue loading. Torsion and fatigue loadings are new features over the second generation of RAMS (RAMS II) that has been (and is still being) used with many user experiments at CHESS.

Read more on the CHESS website

Image: Staff Scientists Kelly Nygren and Peter Ko worked in tandem with AFRL to commission the RAMS IV

Game on: Science Edition

After AIs mastered Go and Super Mario, Brookhaven scientists have taught them how to “play” experiments at NSLS-II

Inspired by the mastery of artificial intelligence (AI) over games like Go and Super Mario, scientists at the National Synchrotron Light Source II (NSLS-II) trained an AI agent – an autonomous computational program that observes and acts – how to conduct research experiments at superhuman levels by using the same approach. The Brookhaven team published their findings in the journal Machine Learning: Science and Technology and implemented the AI agent as part of the research capabilities at NSLS-II.

As a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE’s Brookhaven National Laboratory, NSLS-II enables scientific studies by more than 2000 researchers each year, offering access to the facility’s ultrabright x-rays. Scientists from all over the world come to the facility to advance their research in areas such as batteries, microelectronics, and drug development. However, time at NSLS-II’s experimental stations – called beamlines – is hard to get because nearly three times as many researchers would like to use them as any one station can handle in a day—despite the facility’s 24/7 operations.

“Since time at our facility is a precious resource, it is our responsibility to be good stewards of that; this means we need to find ways to use this resource more efficiently so that we can enable more science,” said Daniel Olds, beamline scientist at NSLS-II and corresponding author of the study. “One bottleneck is us, the humans who are measuring the samples. We come up with an initial strategy, but adjust it on the fly during the measurement to ensure everything is running smoothly. But we can’t watch the measurement all the time because we also need to eat, sleep and do more than just run the experiment.”

Read more on the Brookhaven website

Image: NSLS-II scientists, Daniel Olds (left) and Phillip Maffettone (right), are ready to let their AI agent level up the rate of discovery at NSLS-II’s PDF beamline.

Credit: Brookhaven National Lab

Cooking pollution more resilient than previously thought

Following research undertaken at Diamond, particulate emissions from cooking have been discovered to stay in the atmosphere for longer than initially thought, causing a prolonged contribution to poor air quality and human health.

A new study, led by researchers at the University of Birmingham, demonstrated how cooking emissions can survive in the atmosphere over several days, rather than being broken up and dispersed.

The team collaborated with Diamond, the University of Bath and the Central Laser Facility to show how these fatty acid molecules react with molecules found naturally in the earth’s atmosphere. During the reaction process, a coating is formed around the outside of the particle that protects the fatty acid inside from gases such as ozone which would otherwise break up the particles.

This research was made possible by using Diamond’s powerful X-ray beamline (I22). For the first time researchers we able to recreate the reaction process in a way that enables it to be studied in laboratory conditions.

Read more on the Diamond website

Dust travelled thousands of miles to enrich hawaiian soils

With its warm weather and sandy beaches, Hawaii is a magnet for tourists every year. This unique ecosystem also attracts soil scientists interested in what surprises may lie beneath their feet.

In a recent paper published in Geoderma, European researchers outline how they used the rich soils of Hawaii to study the critical movement of phosphorous through the environment. By better understanding the amount and type of phosphorus in the soil, they can help crops become more successful and maintain the health of our ecosystems for years to come.

The project was led by Agroscope scientist Dr. Julian Helfenstein, Prof. Emmanuel Frossard with the Institute of Agricultural Sciences, ETH Zurich; and Dr. Christian Vogel, a researcher at the Federal Institute for Materials Research and Testing in Berlin.

The team used the Canadian Light Source (CLS) at the University of Saskatchewan to help analyze the different types of phosphorus in their samples and track their origins.

Read more on the Canadian Light Source website

Image: Dr. Christian Vogel using the VLS-PGM beamline to analyze a sample at the CLS.

A new approach for studying electric charge arrangements in a superconductor

X-ray scattering yields new information on “charge density waves”

High-temperature superconductors are a class of materials that can conduct electricity with almost zero resistance at temperatures that are relatively high compared to their standard counterparts, which must be chilled to nearly absolute zero—the coldest temperature possible. The high-temperature materials are exciting because they hold the possibility of revolutionizing modern life, such as by facilitating ultra-efficient energy transmission or being used to create cutting-edge quantum computers.

One particular group of high-temperature superconductors, the cuprates, has been studied for 30 years, yet scientists still cannot fully explain how they work: What goes on inside a “typical” cuprate?

Piecing together a complete picture of their electronic behavior is vital to engineering the “holy grail” of cuprates: a versatile, robust material that can superconduct at room temperature and ambient pressure.

Read more on the NSLS-II website

Image: Brookhaven Lab scientist Mark Dean used the Soft Inelastic X-Ray (SIX) beamline at the National Synchrotron Light Source II (NSLS-II) to unveil new insights about a cuperates, a particular group of high-temperature superconductors. Credit: BNL

Get out your vacuum: Scientists find harmful chemicals in household dust

Since the 1970s, chemicals called brominated flame retardants (BFRs) have been added to a host of consumer and household products, ranging from electronics and mattresses to upholstery and carpets. While they were intended to improve fire safety, one form — polybrominated diphenyl ethers, or PBDEs — has proved harmful to human health, specifically our hormonal systems.

Although the use of PBDEs has been restricted in Canada since 2008, older household electronics and furniture with these compounds are still in use. Additionally, the process used to add this chemical to manufactured goods attached the particles very loosely. As a result, the compound tends to shed over time through normal wear and tear.

A growing body of evidence suggests that concentrations of this chemical are higher indoors and that it is present in dust. A team of researchers from the Canadian Light Source (CLS) at the University of Saskatchewan and Memorial University set out to determine whether they could find bromine in household dust using synchrotron X-ray techniques.

Read more on the Canadian Light Source website

Image: Dr. Peter Blanchard, CLS Associate Scientist, standing in the HXMA beamline at the CLS.

Order in the disorder: density fluctuations in amorphous silicon discovered

For the first time, a team at HZB has identified the atomic substructure of amorphous silicon with a resolution of 0.8 nanometres using X-ray and neutron scattering at BESSY II and BER II. Such a-Si:H thin films have been used for decades in solar cells, TFT displays, and detectors. The results show that three different phases form within the amorphous matrix, which dramatically influences the quality and lifetime of the semiconductor layer. The study was selected for the cover of the actual issue of Physical Review Letters.

Silicon does not have to be crystalline, but can also be produced as an amorphous thin film. In such amorphous films, the atomic structure is disordered like in a liquid or glass. If additional hydrogen is incorporated during the production of these thin layers, so-called a-Si:H layers are formed. “Such a-Si:H thin films have been known for decades and are used for various applications, for example as contact layers in world record tandem solar cells made of perovskite and silicon, recently developed by HZB” explains Prof. Klaus Lips from HZB. “With this study, we show that the a-Si:H is by no means a homogeneously amorphous material. The amorphous matrix is interspersed with nanometre-sized areas of varying local density, from cavities to areas of extremely high order,” the physicist comments.

Read more on the BESSY II website

Image: Structural model of highly porous a-Si:H, which was deposited very quickly, calculated based on measurement data. Densely ordered domains (DOD) are drawn in blue and cavities in red. The grey layer represents the disordered a-Si:H matrix. The round sections show the nanostructures enlarged to atomic resolution (below, Si atoms: grey, Si atoms on the surfaces of the voids: red; H: white) © Eike Gericke/HZB

Red and black ink from Egyptian papyri unveil ancient writing practices

Scientists led by the ESRF and the University of Copenhagen have discovered the composition of red and black inks in ancient Egyptian papyri from circa 100-200 AD, leading to different hypotheses about writing practices. The analysis shows that lead was probably used as a dryer rather than as a pigment, similar to its usage in 15th century Europe during the development of oil paintings. They publish their results today in PNAS.

The earliest examples of preserving human thought by applying ink on a flexible and durable material, papyrus, are found in ancient Egypt at the dawn of recorded history (c. 3200 BCE). Egyptians used black ink for writing the main body of text, while red ink was often used to highlight headings, instructions or keywords. During the last decade, many scientific studies have been conducted to elucidate the invention and history of ink in ancient Egypt and in the Mediterranean cultures, for instance ancient Greece and Rome.

Read more on The European Synchrotron website

Image: Detail of a medical treatise (inv. P. Carlsberg 930) from the Tebtunis temple library with headings marked in red ink. Credit: The Papyrus Carlsberg Collection and the ESRF.

Electron and X‑ray Focused Beam-Induced Cross-Linking in Liquids:

Toward Rapid Continuous 3D Nanoprinting and Interfacing using Soft Materials

Modern additive fabrication of three-dimensional (3D) micron to centimeter size constructs made of polymers and soft materials has immensely benefited from the development of photocurable formulations suitable for optical photolithography,holographic,and stereolithographymethods. Recent implementation of multiphoton laser polymerization and its coupling with advanced irradiation schemes has drastically improved the writing rates and resolution, which now approaches the 100 nm range. Alternatively, traditional electron beam lithography and its variations such as electron-beam chemical lithography, etc. rely on tightly focused electron beams and a high interaction cross-section of 0.1−10 keV electrons with the matter and have been routinely used for complex patterning of polymer resists, self-assembled monolayers, and dried gel films with up to a few nanometers accuracy.

Similarly, a significant progress has been made in deep X-ray lithography, direct writing with zone plate focused X-ray beams for precise, and chemically selective fabrication of high aspect ratio microstructures. Reduced radiation damage within the so-called “water window” has spurred wide biomedical X-ray spectroscopy, microscopy, and tomography research including material processing, for example, gels related controlled swelling and polymerization inside live systems, particles encapsulations,and high aspect ratio structures fabrication.The potential of focused X-rays for additive fabrication through the deposition from gas-phase precursors or from liquid solutions is now well recognized and is becoming an active area of research.

Read more on the Elettra website

Image: The electron/X-ray beam gelation in liquid polymer solution through a SiN ultrathin membrane. Varying the energy and focus of the soft X-rays smaller or larger excitation volumes and therefore finer or wider feature sizes and patterns can be generated.