Latest-News – Page 118 – Lightsources.org

Scientists find ordered magnetic patterns in disordered magnetic material

2018/06/082018/06/11

Study led by Berkeley Lab scientists relies on high-resolution microscopy techniques to confirm nanoscale magnetic features.

A team of scientists working at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has confirmed a special property known as “chirality” – which potentially could be exploited to transmit and store data in a new way – in nanometers-thick samples of multilayer materials that have a disordered structure.

While most electronic devices rely on the flow of electrons’ charge, the scientific community is feverishly searching for new ways to revolutionize electronics by designing materials and methods to control other inherent electron traits, such as their orbits around atoms and their spin, which can be thought of as a compass needle tuned to face in different directions.

These properties, scientists hope, can enable faster, smaller, and more reliable data storage by facilitating spintronics – one facet of which is the use of spin current to manipulate domains and domain walls. Spintronics-driven devices could generate less heat and require less power than conventional devices.

In the latest study, detailed in the May 23 online edition of the journal Advanced Materials, scientists working at Berkeley Lab’s Molecular Foundry and Advanced Light Source (ALS) confirmed a chirality, or handedness, in the transition regions – called domain walls – between neighboring magnetic domains that have opposite spins.

Scientists hope to control chirality – analogous to right-handedness or left-handedness – to control magnetic domains and convey zeros and ones as in conventional computer memory.

Image: (extract, here original image)The top row shows electron phase, the second row shows magnetic induction, and the bottom row shows schematics for the simulated phase of different magnetic domain features in multilayer material samples. The first column is for a symmetric thin-film material and the second column is for an asymmetric thin film containing gadolinium and cobalt. The scale bars are 200 nanometers (billionths of a meter). The dashed lines indicate domain walls and the arrows indicate the chirality or “handedness.” The underlying images in the top two rows were producing using a technique at Berkeley Lab’s Molecular Foundry known as Lorentz microscopy.
Credit: Berkeley Lab

New forensic DNA profiling technique on the horizon

2018/06/082018/06/18

A study recently conducted at the Circular Dichroism beamline (B23) here at Diamond Light Source could pave the way to a new forensic DNA profiling technique. Researchers hailing from the Ivanovo State University of Chemistry and Technology, Russia, The University of Southampton and Diamond investigated the application of specially designed DNA building blocks.

DNA is a versatile template that can be used for a variety of applications. It is made up of building blocks known as nucleotides (labelled A, C, G and T) which form long strands that bind to complementary sequences and give the familiar double helix. The nucleotides can be tailor made to build new functional molecules for biotechnology, analytics, or even materials science.

Takeuchi Receives European Inventor Award 2018

2018/06/072018/06/11

Prolific patent-holder won for inventing battery that increases the lifespan of implantable defibrillators fivefold, greatly reducing need for reoccurring surgery.

Esther Sans Takeuchi, PhD, has won the 2018 European Inventor Award in the “Non-EPO countries”, the European Patent Office (EPO) announced today. The award was given to her by the EPO at a ceremony held today in Paris, Saint-Germain-en-Laye. Of the four U.S. scientists nominated for the award, Takeuchi is the only American to bring home Europe’s most prestigious prize of innovation.

Takeuchi is the Chief Scientist of the Energy Sciences Directorate at the U.S. Department of Energy’s Brookhaven National Laboratory, Stony Brook University’s (SBU) William and Jane Knapp Endowed Chair in Energy and the Environment, and a Distinguished Professor of Chemistry in the College of Arts & Sciences and in Materials Science and Chemical Engineering in the College of Engineering and Applied Sciences at SBU. She was honored for developing the compact batteries that power tiny, implantable cardiac defibrillators (ICDs)—devices that detect and correct irregular, potentially fatal, heart rhythms. Her lithium silver vanadium oxide (“Li/SVO”) battery extended the power-source lifetime for ICDs to around five years, considerably longer than its predecessors, thus reducing the number of surgeries patients needed to undergo to replace them. Her invention led not only to an advance in battery chemistry, but also enabled the production and widespread adoption of ICDs and significantly improved patient well-being.

Image: Esther Sans Takeuchi, a joint appointee of Brookhaven National Laboratory and Stony Brook University, has won the 2018 European Inventor Award in the category “Non-EPO countries.”

Megachirella -the mother of all lizards

2018/06/062018/06/08

A new international research rewrites the history of reptiles starting from a fossil found in the Dolomites.

The origin of lizards and snakes should be pushed back by about 75 million years, as documented by a small reptile, Megachirella wachtleri, found almost 20 years ago in the Dolomites and rediscovered today thanks to cutting-edge techniques in the field of 3D analysis and the reconstruction of evolutionary relationships. Evidence to this effect has been provided by an international paleontological research with the participation of the MUSE Science Museum of Trento, in collaboration with the “Abdus Salam” International Centre of Theoretical Physics of Trieste, the Enrico Fermi Centre of Rome and Elettra Sincrotrone Trieste. The results have been published in the prestigious science journal Nature, which has also dedicated its cover image to research.

The international team has identified Megachirella wachtleri – a small reptile which lived approximately 240 million years ago in what are today the Dolomites – the most ancient lizard in the world thereby providing key insight into the evolution of modern lizards and snakes.
The data – obtained by 3D X-ray imaging techniques and the analysis of DNA sequences – suggest that the origin of “squamates”, i.e. the group comprising lizards and snakes,is older than previously thought and that it can be dated to approximately 250 million years ago, before the most extensive mass extinction in history.

Image: Megachirellawandering amidst the lush vegetation that approximately 240 million years ago surrounded the dolomitic beaches.
Credit: Davide Bonadonna

New director of Berkeley Lab’s Advanced Light Source

2018/06/062018/06/08

After an international search, Stephen D. “Steve” Kevan has been named the new director of the Advanced Light Source (ALS) at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

The ALS produces extremely bright X-ray, infrared, and extreme ultraviolet light for more than 2,000 visiting scientists each year. Up to 40 experiments can be performed simultaneously using the synchrotron, resulting in nearly 1,000 peer-reviewed scientific articles each year across a range of fields, from chemistry and materials sciences to biology and environmental sciences. The facility draws on the Lab’s unique and long-standing expertise in designing, building, and operating world-class accelerators to advance scientific research.

Kevan, a condensed matter physicist, has served as ALS director in an interim capacity since January, when the preceding director, Roger Falcone, stepped down after more than 11 years in the role. Previously, Kevan was the ALS division deputy for science for more than five years and has been on the faculty of the University of Oregon’s physics department since 1986.

Kevan takes on the role of ALS director at a pivotal point in its history. The facility, which will celebrate its 25th anniversary later this year, is taking its first steps toward a major upgrade, dubbed “ALS-U.”

Image: Steve Kevan

Perovskites, the rising star for energy harvesting

2018/06/052018/06/18

Perovskites are promising candidates for photovoltaic cells, having reached an energy harvesting of more than 20% while it took silicon three decades to reach an equivalent. Scientists from all over the world are exploring these materials at the ESRF.

Photovoltaic (PV) panels exist in our society since several years now. The photovoltaic market is currently dominated by wafer-based photovoltaics or first generation PVs, namely the traditional crystalline silicon cells, which take a 90% of the market share.

Although silicon (Si) is an abundant material and the price of Si-PV has dropped in the past years, their manufacturing require costly facilities. In addition, their fabrication typically takes place in countries that rely on carbon-intensive forms of electricity generation (high carbon footprint).

But there is room for hope. There is a third generation of PV: those based on thin-film cells. These absorb light more efficiently and they currently take 10% of the market share.

Image: The CEA-CNRS team on ID01. From left to right: Peter Reiss, from CEA-Grenoble/INAC, Tobias Schulli from ID01, Tao Zhou from ID01, Asma Aicha Medjahed, Stephanie Pouget (both from CEA-Grenoble/INAC) and David Djurado, from the CNRS.
Credits: C. Argoud.

Real-time ptychographic data streaming

2018/06/042018/06/14

CAMERA/ALS/STROBE Collaboration yields novel image data workflow pipeline.

What began nearly a decade ago as a Berkeley Lab Laboratory-Directed Research and Development (LDRD) proposal is now a reality, and it is already changing the way scientists run experiments at the Advanced Light Source (ALS)—and, eventually, other light sources across the Department of Energy (DOE) complex—by enabling real-time streaming of ptychographic image data in a production environment.

In scientific experiments, ptychographic imaging combines scanning microscopy with diffraction measurements to characterize the structure and properties of matter and materials. While the method has been around for some 50 years, broad utilization has been hampered by the fact that the experimental process was slow and the computational processing of the data to produce a reconstructed image was expensive. But in recent years advances in detectors and x-ray microscopes at light sources such as the ALS have made it possible to measure a ptychographic dataset in seconds.

>Read more on the Berkeley Lab website

Picture: The modular, scalable Nanosurveyor II system—now up and running at the ALS—employs a two-sided infrastructure that integrates the ptychographic image data acquisition, preprocessing, transmission and visualization processes.

Big science -literally- at ESRF

2018/06/012018/06/07

This is no ordinary experiment. With a huge detector in tow and a team of 15 scientists from Goethe University in Frankfurt (Germany), it is probably as big as science gets -literally.

A 4-metre-long lorry arrived at the ESRF with a precious load: a so-called COLTRIMS Reaction Microscope. The chamber is so big that it requires a crane to fit it into the experimental hutch of ID31. And lots of manpower to set the experiment up. The aim: to image the momentum distribution of one of the two electrons in the Helium atom without averaging over the momentum distribution of the other, offering the most complete and detailed view on electron correlation.

The COLTRIMS technique allows the team to measure event by event the initial state momentum of a Compton scattered electron of a Helium atom and, in coincidence with this, they measure the second electron’s momentum as it is shaken off.

Image: The team was in high spirits throughout the two-week duration of the experiment.
Credits: M. Kircher.

Stable solvent for solution-based electrical doping…

2018/05/312018/06/07

… of semiconducting polymer films and its application to organic solar cells.

Controlled and stable electrical doping of organic semiconductors is desirable for the realization of efficient organic photovoltaic (OPV) devices. Thus, progress has been made to understand the fundamental doping mechanisms.1-3 In 2016, Aizawa et al. reported the use of 12-molybdophosphoric acid hydrate (PMA) to induce p-type doping and crosslinking of neat films of poly[N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyl-2’,1’,3’-benzothiadiazole)](PCDTBT).4 Later on, a more general approach of sequential solution-based doping was presented, by post-process immersion of donor-like polymer films in PMA-nitromethane solutions.5 However, critical to the method is the use of nitromethane, a highly unstable solvent, to dissolve PMA and thus limited the applicability to large-scale fabrication of organic solar cells.

A collaboration between a team of researchers from the Kippelen Research Group at Georgia Tech and the Toney Research Group at SSRL developed a solution-based doping method using the highly stable solvent, acetonitrile. Figure 1a displays the chemicals used in this work. In Figure 1b, the optical properties of poly(3-hexylthiophene-2,5-diyl)(P3HT) films immersed for 30 min in a 0.5 M solution of PMA in acetonitrile (PMA-im-P3HT) were studied by comparing their transmittance spectra against pristine P3HT and P3HT immersed similarly in a 0.5 M solution of PMA in nitromethane. The normalized change of transmittance ΔT T-1 as a function of wavelength (inset of Fig.1b) reveals the same spectral signatures reported for PMA-im-P3HT films when PMA was dissolved in nitromethane. That is, changes in the region where ΔT T-1< 0 correlate with the P3HT polaron bands, and deviations in the region where ΔT T-1> 0 correlate to the bleaching of the main π-π* absorption bands.6 The data suggests electrical p-doping into the depth of the organic film. Figure 1c shows that the performance of PMA-doped OPV devices using PMA in acetonitrile is comparable to that of OPVs made using PMA in nitromethane or MoO3, under simulated AM 1.5G solar illumination. Furthermore, if the light soaking mechanism is used before each measurement, OPVs made using PMA in nitromethane or acetonitrile remain stable for up to 524 h in the air, retaining 80% of their initial power conversion efficiency (PCE).

Figure: (extract) of GIWAXS data as measured on pristine and PMA doped P3HT, when using various solvents to dissolve the PMA. a, Two-dimensional GIWAXS data converted to q-space for pristine P3HT and P3HT immersed in PMA solutions in nitromethane, acetonitrile or ethanol for 60 seconds. b, One-dimensional scattering profiles (out-of-plane and in-plane profiles), obtained from the two-dimensional GIWAXS data.

UBC scientists break down tuberculosis structure

2018/05/302018/05/31

Scientists from the University of British Columbia have taken a crucial step towards starving out tuberculosis, following research into how the infection grows in the body.

Tuberculosis, a bacterial infection which generally affects the lungs, is a global threat; worldwide, it kills more people than HIV and malaria combined. In Canada, there are around 1,600 new cases of tuberculosis reported every year, with about 20 per cent of those cases affecting First Nations peoples, according to the Government of Canada. Researchers using the Canadian Light Source have investigated how the bacteria grow in lungs in an effort to better understand how tuberculosis can be treated.

Lindsay Eltis, a UBC professor of Microbiology and Immunology and Canada Research Chair in Microbial Catabolism and Biocatalysis, has spent the last 25 years studying bacteria and determining how they grow on different compounds. In 2007, Eltis’ group discovered that tuberculosis bacteria grow on cholesterol and that this is important for causing disease.

“Many bacteria, like humans, grow using glucose, a type of sugar. They derive energy from it, converting it to water and carbon dioxide, and use it to make building blocks essential to life. The tuberculosis bacterium is a bit unusual in that it can grow on cholesterol, deriving energy and essential building blocks from it,” explains Eltis. “This ability to grow on cholesterol helps the bacterium establish infection in our lungs.”

Image: Crystal structure of the newly imaged carbon-ring cleaving enzyme from the tuberculosis bacterium, IpdAB_Mtb.
Credit: Lindsay Eltis

ALS passes the 7000-protein milestone

2018/05/302018/06/11

The eight structural biology beamlines at the ALS have now collectively deposited over 7000 proteins into the Protein Data Bank (PDB), a worldwide, open-access repository of protein structures. The 7000th ALS protein structure (entry no. 6C7C) is an enzyme from Mycobacterium ulcerans (strain Agy99), solved with data from Beamline 5.0.2. This bacterium produces a toxin that eats away at skin tissue, causing what’s known as Buruli ulcers (Google at your own risk!). The bacterium is antibiotic-resistant, and treatment involves the surgical removal of infected tissues, including amputation.

The enzyme structure was solved by a group from the Seattle Structural Genomics Center for Infectious Disease (SSGID), whose mission is to obtain crystal structures of potential drug targets on the priority pathogen list of the National Institute of Allergy and Infectious Diseases (NIAID). As of May 2018, SSGCID has deposited 1090 structures in the PDB, with data for more than a quarter of those collected at ALS beamlines.

Image: PDB 6C7C: Enoyl-CoA hydratase, an enzyme from M. ulcerans (strain Agy99).

Synchrotron X-rays reveal identity of 1.5 million-year-old Tuscan big cat

2018/05/292018/05/31

The identity of a mysterious fossil felid found in central Italy has been revealed thanks to synchrotron techniques.

Scientists used X-ray tomography to virtually extract the fossil from its rock encasing and describe decisive anatomical details for the first time. Previously thought to be an extinct Eurasian jaguar, this new study concluded by identifying the felid as Acinonyx pardinensis, one of the most intriguing extinct carnivores of the Old World Plio-Pleistocene. The study is published in Scientific Reports.

The team of physicists and palaeontologists from the University of Perugia, the University of Verona and the University of Rome Sapienza, in collaboration with the European Synchrotron, ESRF, scanned the partial skull of the specimen, still embedded in the rock. The analysis of images and 3D models obtained revealed a mosaic of cheetah-like teeth and Panthera-like features leading to a reconsideration of the ecological role of this species.

Image: Dawid Iurino with the Acinonyx pardinensis skull from Monte Argentario, on the set-up of ESRF ID17 beamline.
Credit: Marco Cherin

New high-precision instrument enables rapid measurements of protein crystals

2018/05/292018/05/31

A team of scientists and engineers at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new scientific instrument that enables ultra-precise and high-speed characterization of protein crystals at the National Synchrotron Light Source II (NSLS-II)—a DOE Office of Science User Facility at Brookhaven, which generates high energy x-rays that can be harnessed to probe the protein crystals. Called the FastForward MX goniometer, this advanced instrument will significantly increase the efficiency of protein crystallography by reducing the run time of experiments from hours to minutes.

Protein crystallography is an essential research technique that uses x-ray diffraction for uncovering the 3D structures of proteins and other complex biological molecules, and understanding their function within our cells. Using this knowledge about the basic structure of life, scientists can advance drug design, improve medical treatments, and unravel other environmental and biochemical processes governing our everyday lives.

>Read more on the NSLS-II website

Image: Yuan Gao, Wuxian Shi, Evgeny Nazaretski, Stuart Myers, Weihe Xu and, Martin Fuchs designed and implemented the new goniometer scanner system for ultra-fast and efficient serial protein crystallography at the Frontier Microfocusing Macromolecular Crystallography (FMX) beamline at the National Synchrotron Light Source II.

Ferromagnetic and antiferromagnetic coupling of spin molecular interfaces

2018/05/282018/05/31

Researchers from the physics department of the Università “La Sapienza” in Rome, Centro S3 of Modena and ALBA, have demonstrated that magnetic coupling of metal-organic molecules to a magnetic substrate mediated by a graphene layer can be tuned in strength and direction by choosing the symmetry of the molecular orbitals that is largely preserved thanks to the graphene layer. The results have been published in the journal Nano Letters.

Paramagnetic molecules become potential building blocks in spintronics when their magnetic moments are stabilized against thermal fluctuations, for example, by a controlled interaction with a magnetic substrate. Spin molecular interfaces with preserved magnetic activity and exhibiting magnetic remanence at room temperature (RT) can open the route to engineer highly spin-polarized, nanoscale current sources. The need to fully control the organic spin interface and the tuning of ferromagnetic (FM) or antiferromagnetic (AFM) coupling to achieve a stable conductance has motivated a vast experimental interest.

>Read more on the ALBA website

Image: Figure 1: a,b) Antiferromagnetic/Ferromagnetic coupling as deduced by element-specific hysteresis loops of a FePc and CuPc (respectively) to a Cobalt layer with perpendicular magnetic anisotropy intercalated below graphene. c,d) orbital-porjection of the spin-density for the FePc and CoPc interface reflecting the different symmetry of the molecular orbitals involved in the ferromagnetic and antiferromagnetic interaction.

The power supplies giving Diamond a boost

2018/05/242018/05/25

The electrons that produce Diamond’s ultra-bright light whizz round the storage ring fast enough to travel around the entire world 7.5 times in a single second. But they don’t start out life super speedy, and they need a huge energy boost to get them ready for work!

Diamond’s electrons are generated in the injection system, where they are produced by a glowing filament (just like a dim light bulb) and accelerated to ninety thousand electron volts (90 keV). From there, a linear accelerator (linac) takes over, accelerating the electrons to a hundred million electron volts (100 MeV, or 0.1 GeV).

That’s not fast enough though, so the electrons from the linac are fed into the booster ring, where they’re are accelerated to 3 GeV by passing through an RF cavity millions of times. It’s like microwaving the electrons to get them to accelerate, which is not an easy task. The electrons want to travel in a straight line, and have to be forced to bend around the ring by dipole bending magnets. As the energy of the electrons increases, it gets harder to keep them moving around the booster ring, and the bending magnets need more power.

Image: Members of the Power Supply team working in the Booster Supply Hall.

Rational optimization of organic solar-cell materials

2018/05/222018/06/07

The work suggests a way to quickly identify ideal material mixtures and processing methods, bypassing trial-and-error strategies and minimizing labor-intensive synthesis.

To generate electricity from light, the photoactive layer of an organic solar cell (OSC) must allow the photoexcitation and separation of charges, something that can happen in blends of electron-donating and electron-accepting organic materials. Not surprisingly, such blends have been created in steady succession with the goal of improving device efficiency.

However, there are over a thousand combinations of electron donors and acceptors available for use in OSCs and countless processing variations. The reliance on trial and error to identify the best materials and methods is a serious limitation. A way to predict device efficiency based on easily measurable or derivable parameters would go a long way toward streamlining the process.

Image: (extract) Artistic interpretation of an organic solar-cell mixture containing a blend of polymers and fullerenes. Interactions between these molecules (represented by the interaction parameter, χ) affect the degree of mixing that occurs, which in turn is key to device performance.