In search of the perfect system

Researchers take a new approach to improve widely used biotechnology tool

The unique relationship between an essential vitamin and a purified bacterial protein has been used as a valuable tool in science and medicine for several decades. Together these two molecules, known as streptavidin and biotin, form a very strong and specific interaction that is invaluable for many biotechnological applications.

Labeling molecules with biotin and detecting them with streptavidin is a common part of many lab tests and has enabled many scientific discoveries in medicine. Streptavidin and biotin are as essential to lab technicians as hammers and nails are to a carpenter. The two molecules combine to form “molecular glue” for many of the tests used to diagnose infectious diseases like HIV, Hepatitis C and Lyme disease, to discover new proteins, viruses and bacteria, and to explore how molecules function in living organisms.

Read more on the Canadian Light Source website

Image: Trapped biotin: A crystal structure of the M88 mutein, determined at the CMCF beamline at CLS, reveals how the engineered disulphide formed between Cys49 and Cys86 (green spheres) partially block the exit pathway for biotin (magenta spheres). Credit: CLS

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.

Powering the future of clean energy

Hydrogen gas can be used to power vehicles and has the potential to provide electricity to homes

The global quest for clean energy is championed by researchers in Canada who are focused on harnessing the potential of hydrogen.

The idea of the hydrogen economy was first proposed 50 years ago as a way to combat the negative effects of fossil fuels. Its future is the focus of new research from the University of Toronto’s Thermofluids for Energy and Advanced Materials (TEAM) lab, whose work relied on the Canadian Light Source (CLS) at the University of Saskatchewan to visualize performance.

Read more on the Canadian Light Source website

Image: Adam Webb (CLS), Sergey Gasilov (CLS), Manojkumar Balakrishnan (U of T), Jason Keonhag Lee (U of T), Denise Miller (CLS), Kieran Fahy (U of T) on the BMIT beamline at CLS.

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.

Orbital angular momentum carried by an optical field can be imprinted onto a propagating electron wave

Photons have fixed spin and unbounded orbital angular momentum (OAM). While the former is manifested in the polarization of light, the latter corresponds to the spatial phase distribution of its wavefront. The distinctive way in which the photon spin dictates the electron motion upon light–matter interaction is the basis for numerous well-established spectroscopies. By contrast, imprinting OAM on a matter wave, specifically on a propagating electron, is generally considered very challenging and the anticipated effect undetectable.

We carried out an experiment at the LDM beam line at the FERMI free-electron laser, with the aim of inducing an OAM-dependent dichroic photoelectric effect on photo-electrons emitted by a sample of He atoms. The experiment involved a large international collaboration and surprisingly confirmed that the spatial distribution of an optical field with vortex phase profile can be imprinted coherently on a photoelectron wave packet that recedes from an atom. Our results explore new aspects of light–matter interaction and point to qualitatively novel analytical tools, which can be used to study, for example, the electronic structure of intrinsic chiral organic molecules. The results have been published in Nature Photonics.

Read more on the Elettra website

Image: A VUV free-electron laser (violet) is used to ionize a sample of He atoms, and an infrared beam (red) to imprint orbital angular momentum on photo-emitted electrons. Credit: J. Wätzel (Halle university)

Producing less costly, greener hydrogen peroxide

Australian researchers led by the University of New South Wales have used the Australian Synchrotron to understand how the chemical structure of an advanced catalytic material contributes to its stability and efficiency. The approach has the potential to produce hydrogen peroxide (H2O2) in a process that is cost-effective with less harm to the environment.

Hydrogen peroxide is an important chemical that used widely in a range of applications, including wastewater treatment, disinfection, paper/pulp bleaching, semi-conductor cleaning, mining and metal processing, fuel cells and in chemical synthesis.

According to an international market research group, IMARC, the global hydrogen peroxide market size was valued at US$4.0 billion in 2017 and is increasing.

Read more on the ANSTO website

Image: The optimized geometry structures of bare CoN4 moiety and CoN4 moieties with different coverages of epoxy oxygen. The gray, blue, orange and red balls represent C, N, Co and O atoms, respectively [Reprinted with permission by Creative Commons License: Attribution 4.0 International (CC BY 4.0)]

Secrets of spider web strength revealed

An international collaboration between the University of MelbourneUniversity of Bayreuth and ANSTO’s Australian Synchrotron provides the first insights into how the rare silk of the Australian basket-web spider retains its strength and resilient structure— allowing the spider to make a robust and rather exquisite silken basket.  

The silk is so firm and remarkable that it enables the basket web to maintain its structural integrity without any support from the surrounding vegetation.

The insights into physical and chemical properties of this basket-web silk may be useful for the production of artificial spider silks, which have already shown strong potential as an advanced biomimetic material in textile and medical applications.

“The biochemical makeup of the silk thread cross-section, particularly secondary protein structures and complex carbohydrates, was examined on the Infrared Microspectroscopy (IRM) beamline at the Australian Synchrotron,” said beamline scientist and co-author, Dr Pimm Vongsvivut.

Read more on the ANSTO website

Image: Credit:  Hanyl et al, “Free-standing spider silk webs of the thomisid Saccodomus Formivorus are made of composites comprising micro- and submicron fibers,” Scientific Reports10, 17624 (2020)

Protecting Saskatchewan lakes from contamination

Using the Canadian Light Source synchrotron, a University of Saskatchewan-led research team has developed a method for monitoring uranium contaminants in mine tailings using samples from McClean Lake, SK.

While mining companies work to extract as much uranium as possible from processed ore, small amounts remain in the solid and liquid residue—called tailings—left over from the milling process.

To protect the downstream environment from potential impacts of the solid waste, the Canadian Nuclear Safety Commission requires companies to monitor the chemistry of uranium and other potentially harmful elements in their tailings facilities.

Numerous researchers have studied the chemistry of nickel, arsenic, selenium and molybdenum in Orano Canada’s tailings management facility at McClean Lake, but to date little was known about residual uranium. One of the challenges has been the extremely low concentrations of the element left after processing at Orano’s ore mill, which began operating in 1997.

Read more on the Canadian Light Source website

Image: Arthur Situm conducting research at SXRMB beamline. Photo by David Stobbe for USask.

Diamond helps uncover how an untreatable cancer-causing virus affects immune cells

Scientists have found that human T-cell lymphotropic virus, type 1 (HTLV-1) hijacks cellular machinery to establish an infection.  

Research was undertaken using cutting-edge visualisation techniques such as X-ray crystallography, which was undertaken at Diamond, and single-particle cryo-electron microscopy (cryo-EM).  

HTLV-1 is a virus that affects T cells, a type of white blood cell which plays a crucial role in our immune system. Currently, between five and 20 million people worldwide are infected by HTLV-1 and no cure or treatment is available. While most people infected with the virus do not experience symptoms, around two to five per cent will go on to develop adult T-cell leukaemia (ATL).  

New research, led by a team from Imperial College London and the Francis Crick Institute, shows in atomic detail how HTLV-1 infects immune cells. By providing a more nuanced understanding of how the virus establishes infection in the body, the research will help to support the development of new, targeted therapies. 

Read more on the Diamond Light Source website

Image: Scanning electron micrograph of a human T lymphocyte (also called a T cell) from the immune system of a healthy donor. Credit: NIAID

Transition-metal dichalcogenide NiTe2: an ambient-stable material for catalysis and nanoelectronics

Recently, transition-metal dichalcogenides hosting topological states have attracted considerable attention for their potential implications for catalysis and nanoelectronics. The investigation of their chemical reactivity and ambient stability of these materials is crucial in order to assess the suitability of technology transfer. With this aim, an international team of researchers from Italy, Russia, China, USA, India, and Taiwan has studied physicochemical properties of NiTe2 by means of several experimental techniques and density functional theory. Surface chemical reactivity and ambient stability were followed by x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) experiments at the BACH beamline, while the electronic band structure was probed by spin- and angle-resolved photoelectron spectroscopy (spin-ARPES) at the APE-LE beamline

Read more on the Elettra website

Image: a) Ni-3p core-level spectra collected from as-cleaved NiTe2 (black curves) and from the same surface exposed to 2·10L of CO (red curves), H2O (green curves) and O2 (blue curves).  Credit: Adapted from “S. Nappini et al., Adv. Funct. Mater. 30, 2000915 (2020); DOI: 10.1002/adfm.202000915” with permission from Wiley (Copyright 2020) with license 4873681106527

Observation of flat bands in twisted bilayer graphene

Magic-angle materials represent a surprising recent physics discovery in double layers of graphene, the two-dimensional material made of carbon atoms in a hexagonal pattern. 

When the upper layer of two stacked layers of graphene is rotated by about 1 degree, the material suddenly turns into a superconductor. At a temperature of 3 Kelvin, this so-called twisted bilayer graphene (tbg) conducts electricity without resistance.

Now, an international team of scientists from Geneva, Barcelona, and Leiden have finally confirmed the mechanism behind this new type of superconductors. In Nature Physics, they show that the slight twist causes the electrons in the material to slow down enough to sense each other. This enables them to form the electron pairs which are necessary for superconductivity.

How can such a small twist make such a big difference? This is connected with moiré patterns, a phenomenon also seen in the everyday world. When two patterned fences are in front of another, one observes additional dark and bright spots, caused by the varying overlap between the patterns. Such moiré patterns (derived from the the French name of textile patterns made in a similar way) generally appear where periodical structures overlap imperfectly.

Read more on the Elettra website

Image: Angle resolved photoemission spectrum revealing flat non-dispersing electronic band filled with slow electrons separated by mini gaps from the rest of electronic structure in twisted bilayer graphene device.

PHELIX beamline is ready to research

Synchrotron light has finally been observed for the first time on a sample at the end station of the experimental beamline PHELIX. This success is the crowning achievement of three years of hard work designing, constructing, fitting, and tuning its components to the synchrotron beam.   

The installation of this new beamline began in mid-2018. In March of 2020, the final elements were delivered. Then on 18th September 2020, the scientific supervisors of beamline, Dr. Magdalena Szczepanik – Ciba and Tomasz Sobol, announced readiness for test experiments using the synchrotron beam.  

The first results testing the capabilities with the active beam of the analyser at the PHELIX end station were performed using the sample of gold in the presence of a specialist from the SPECS company, Dr. Robert Reichelt. As  a result of testing this calibration material, among others, the XPS Au4f spectrum was acquired (see pic.1). Additionally, an angle – resolved and spin – resolved measurements were performed .

During the latest open call for the beamtime the applications on the PHELIX beamline where included for the first time. This line will use soft X-ray radiation. The end-station will enable a wide range of spectroscopic and absorption researches, characterised by different surface sensitivity. Besides acquiring standard, high-resolution spectra, it will allow e.g. for the mapping of band structure in three dimensions and for the detection of spin in three dimensions.  

Users will thus be able to conduct research on new materials, thin films, and multi-layer systems, catalysers and biomaterials, as well as research on solids, on spin-polarised surface states, and on chemical reactions taking place on the surface.

Read more on the SOLARIS website

Image:  From left Tomasz Sobol, Dr. Robert Reichelt, Dr. Magdalena Szczepanik – Ciba. Credit – Solaris

Lightsource research on SARS-CoV-2

Coronaviruses are a family which includes the common cold, SARS, MERS and the current outbreak of the disease COVID-19, caused by the SARS-CoV-2 virus.
Several facilities of our collaboration have started research about SARS-CoV-2 virus or launched open calls for rapid access. This post will be updated regularly.

Publications on SARS-CoV-2 Rapid Access




Publications

BESSY II at HZB (Germany) has set up a page where it shows their contributions to the research on SARS-CoV-2 , see here

DESY (Germany) has launched a new page dedicated to Corona Research: https://www.desy.de/news/corona_research/index_eng.html

Diamond Light Source (UK) has created a specific website “Coronavirus Science” with platforms for various audiences: scientific community, general public and the media: https://www.diamond.ac.uk/covid-19.html

ELETTRA (Italy) has launched a new page dedicated to COVID-19 research: https://www.elettra.eu/science/covid-19-research-at-elettra.html

The Photon Division of PSI (Switzerland) have collated many information linked to their institute on coronavirus-relevant research (recent publications, rapid access…): https://www.psi.ch/en/psd/covid-19

Published articles

2020.10.07 National Synchrotron Light Source II (NSLS-II) at Brookhaven Lab (NY / USA) article on their website: Steady Progress in the Battle Against COVID-19

2020.10.07 Diamond Light Source (UK), article on their website: Structural Biology identifies new information to accelerate structure-based drug design against COVID-19

2020.10.06 MAX IV (Sweden), article on their website: Tackling SARS CoV-2 viral genome replication machinery using X-rays

2020.08.31 SLAC (CA / USA), article also with news about research at Stanford Synchrotron Radiation Lightsource (SSRL): SARS-CoV-2 Spike Protein Targeted for Vaccine

2020.08.27 Diamond Light Source (UK), article on their website: Structural Biology reveals new target to neutralise COVID-19

2020.08.27 Canadian Light Source (Canada) video on their website: Developing more effective drugs

2020.08.25 Australian Synchrotron (ANSTO) (Australia) article on their website: More progress on understanding COVID-19

2020.08.24 DESY (Germany) article on their website: PETRA III provides new insights into COVID-19 lung tissue

2020.08.11 Australian Synchrotron (ANSTO) (Australia) article on their website: Unique immune system of the alpaca being used in COVID-19 research

2020.07.30 Swiss Light Source at PSI (Switzerland) article on their website: COVID-19 research: Anti-viral strategy with double effect

2020.07.29 National Synchrotron Light Source II (NSLS-II) at Brookhaven Lab (NY / USA) article on their website: Ready to join the fight against COVID-19.

2020.07.20 ALBA (Spain) article on their website: A research team from Centro de Investigaciones Biológicas Margarita Salas (CIB-CSIC) uses synchrotron light to study the possible effect of an antitumoral drug of clinical use over the viral cycle of SARS-CoV-2 coronavirus. 

2020.07.15 ALS (USA) article on their website: Antibody from SARS Survivor Neutralizes SARS-CoV-2

2020.07.14 Diamond Light Source (UK), article on their website: Engineered llama antibodies neutralise Covid-19 virus

2020.06.17 European XFEL (Germany) article on their website: Pulling Together: A collaborative research approach to study COVID-19

2020.06.15 European XFEL (Germany) article on their website: Open Science COVID19 analysis platform online

2020.06.09 APS at Argonne National Laboratory (USA) article on their website: Novel Coronavirus Research at the Advanced Photon Source

2020.05. Società Italiana di Fisica publishes an article about research done at Elettra Sincrotrone Trieste (Italy) and the Advanced Light Source (CA / USA): Accelerator facilities support COVID-19-related research

2020.05.27 Diamond Light Source (UK), new animation video demonstrating the work that has been done at Diamond’s XChem facilities.

2020.05.19 Advanced Light Source (CA / USA), article about their latest results: X-ray Experiments Zero in on COVID-19 Antibodies

2020.05.15 Swiss Light Source (Switzerland), article about their first MX results: First MX results of the priority COVID-19 call

2020.05.14 MAX VI (Sweden), article about their research: Tackling SARS CoV-2 viral genome replication machinery using X-rays

2020.05.14 CHESS (NY/USA), article: CHESS to restart in June for COVID-19 research

2020.05.14 the LEAPS initiative brings together many of our European members. The initative published this brochure: Research at LEAPS facilities fighting COVID-19

2020.05.12 Diamond Light Source (UK), article about their collaboration in a consortium: UK consortium launches COVID-19 Protein Portal to provide essential reagents for SARS-CoV-2 research

2020.05.11 Advanced Photon Source (IL/USA), article: Studying Elements from the SARS-CoV-2 Virus at the Bio-CAT Beamline

2020.05.07 European XFEL (Germany), article: European XFEL open for COVID-19 related research

2020.05.06 ESRF (France), article: World X-ray science facilities are contributing to overcoming COVID-19

2020.04.29. BESSY II at HZB (Germany), article: Corona research: Consortium of Berlin research and industry seeks active ingredients

2020.04.29. Swiss Light Source and SwissFEL at PSI (Switzerland), interview series on the PSI website: Research on Covid-19

2020.04.23. PETRA III at DESY (Germany), article: X-ray screening identifies potential candidates for corona drugs

2020.04.21. MAX IV (Sweden), article: BioMAX switches to remote operations in times of COVID-19

2020.04.16. SLAC (CA / USA), article also with news about research at Stanford Synchrotron Radiation Lightsource (SSRL): SLAC joins the global fight against COVID-19

2020.04.15 Berkeley National Lab (CA/ USA), article with a focus on the research at the Advanced Light Source (ALS):
Staff at Berkeley Lab’s X-Ray Facility Mobilize to Support COVID-19-Related Research

2020.04.07 Diamond Light Source (UK), article: Call for Chemists to contribute to the fight against COVID-19
Crowdfunding: COVID-19 Moonshot

2020.04.07. ANSTO’s Australian Synchrotron (Victoria), article: Aiding the global research effort on COVID-19

2020.04.06. National Synchrotron Light Source II (NSLS-II) at Brookhaven Lab (NY / USA), article: Brookhaven Lab Mobilizes Resources in Fight Against COVID-19

2020.04.02. BESSY II at HZB (Germany), article: Corona research: Two days of measuring operation to find the right key

2020.03.31 Diamond Light Source (UK), article: Jointly with Exscientia and Scripps Research, Diamond aims to accelerate the search for drugs to treat COVID-19

2020.03.27 Argonne National Laboratory with the Advanced Photon Source (APS) and other facilities on-site (IL / USA), article: Argonne’s researchers and facilities playing a key role in the fight against COVID-19

2020.03.27 ANSTO’s Australian Synchrotron (Victoria), article and video: Helping in the fight against COVID-19

2020.03.25 PETRA III at DESY (Germany), article: Research team will X-ray coronavirus proteins

2020.03.23 Diamond Light Source (UK) releases its first animation explaining: SARS-CoV-2 Mpro Single Crystal Crystallography

2020.03.25 CERN Courrier (Switzerland) article about synchrotron research on SARS-CoV-2, written by Tessa Charles (accelerator physicist at the University of Melbourne currently based at CERN, completed her PhD at the Australian Synchrotron): Synchrotrons on the coronavirus frontline

2020.03.19 BESSY II at Helmholtz-Zentrum Berlin (Germany), research publication: Coronavirus SARS-CoV2: BESSY II data accelerate drug development

2020.03.19 BESSY II at Helmholtz-Zentrum Berlin (Germany), technique explanation webpage: Protein crystallography at BESSY II: A mighty tool for the search of anti-viral agents

2020.03.16 Diamond Light Source (UK), article on their “Coronavirus Science” website: Main protease structure and XChem fragment screen

2020.03.12. Elettra Sincrotrone (Italy), article on their website: New project to fight the spread of Coronavirus has been approved

2020.03.05. Advanced Photon Source (IL / USA), article on their website: APS Coronavirus Research in the Media Spotlight

2020.03.05. Advanced Photon Source (IL / USA), research publication: “Crystal structure of Nsp15 endoribonuclease NendoU from SARS-CoV-2,” bioRXiv preprint  DOI: 10.1101/2020.03.02.968388, Article on their website (source: Northwestern University): New Coronavirus Protein Reveals Drug Target




Rapid access

Scientists can apply for rapid access at following facilities (only member facilities of Lightsources.org are referenced, the most recent published (or updated) call is mentioned first).

  • The National Synchrotron Light Source II (NSLS-II) in NY / USA is offering a streamlined and expedited rapid access proposal process for groups that require beam time for structural biology projects directly related to COVID-19. The Center for Biomolecular Structure team is supporting remote macromolecular crystallography experiments at Beamlines 17-ID-1 (AMX) and 17-ID-2 (FMX) in this research area. To submit a macromolecular crystallography proposal for COVID-19 related research, use the following form:
    https://surveys.external.bnl.gov/n/RapidAccessProposal.aspx
  • The Advanced Photon Source (APS) at Argonne National Laboratory in IL / USA  user program is operational to support:

·         Research on SARS-CoV-2 or other COVID-19-related research that addresses the current pandemic.

·         Critical, proprietary pharmaceutical research.

·         Mail-in/remote access work for any research involving low-risk samples and most medium-risk samples (as defined on the APS ESAF form).

·         Limited in situ research (set-up with one person, and ability to carry out majority of experiment safely remotely)
https://www.aps.anl.gov/Users-Information/About-Proposals/Apply-for-Time

PETRA III at DESY in Germany offers also Fast Track Access for Corona-related research:
https://photon-science.desy.de/users_area/fast_track_access_for_covid_19/index_eng.html

Australian Synchrotron at ANSTO makes its macromolecular crystallography beamlines available to structural biologists in response to the COVID-19 pandemic: https://www.ansto.gov.au/user-access

North American DOE lightsource facilities have created a platform to enable COVID-19 research. There you can find ressources and points of contact to request priority access:
Structural Biology Resources at DOE Light Sources

Elettra Sincrotrone Trieste in Italy opens to remote acces following beamlines: XRD1, XRD2, SISSI-BIO and MCX thanks to an CERIC-ERIC initiative:
https://www.ceric-eric.eu/2020/03/10/covid-19-fast-track-access/
http://www.elettra.eu/userarea/user-area.html

The Advanced Light Source (ALS) at LBNL in California / USA has capabilities relevant to COVID-19 and researchers can apply through their RAPIDD mechanism:
https://als.lbl.gov/apply-for-beamtime/

ALBA Synchrotron in Spain offers a COVID-19 RAPID ACCESS on all beamlines:
https://www.albasynchrotron.es/en/en/users/call-information

SOLARIS Synchrotron in Poland gives acces to its Cryo Electron Microscope thanks to an CERIC-ERIC initiative: https://www.ceric-eric.eu/2020/03/10/covid-19-fast-track-access/

Swiss Light Source and Swiss FEL at PSI in Switzerland offer priority access to combating COVID-19:
https://www.psi.ch/en/sls/scientific-highlights/priority-access-call-for-work-on-combating-covid-19

Diamond Light Source in the United Kingdom opened also a call for rapid access:
https://www.diamond.ac.uk/Users.html

Image: Electron density at the active site of the SARS-CoV-2 protease, revealing a fragment bound
Credit: Diamond Light Source

Dynamic, yet inertial – and definitely futuristic

Researchers conduct experiments to demonstrate inertial motion in magnetic materials

In the journal Nature Physics (DOI: 10.1038/s41567-020-01040-y), an international team of scientists from Germany, Italy, Sweden, and France report on their experimental observation of an inertial effect of electron spins in magnetic materials, which had previously been predicted, but difficult to demonstrate. The results are the outcome of one of the first long-term projects at the high-power terahertz light source TELBE at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR).

Today, most of the world’s “memory” is stored on magnetic data carriers – hard disks – without which our digital lives would be unthinkable. In the magnetic material, it is the electron spins that do the actual job of storing the data. Imagine this spin as electrons rotating around their own axes, either to the left or right – representing the digital “zeros” and “ones”.

There is something special about this rotation, as Dr. Jan-Christoph Deinert from the HZDR Institute of Radiation Physics explains: “In the magnetic field, the electron behaves like a tumbling spinning top. The rotational axis of the electron changes its direction on a circular path. We call this process precession. When disturbed by an external force, the rotational axis should also make small oscillatory movements, called nutation, which overlap the precession. Like precession, it is a characteristic of many rotating objects, from children’s spinning tops to planets like Earth. Due to its much smaller scale, however, nutation is far more difficult to observe.”

Read more on the Helzholtz Zentrum Dresden Rossendorf website

Image: An international team of scientists has managed for the first time to observe the ‘nutation’ of spins in magnetic materials (the oscillations of their axis during precession). Foto: Dunia Maccagni

Who stole the light?

Self-induced ultrafast demagnetization limits the amount of light diffracted from magnetic samples at soft x-ray energies.

Free electron X-ray lasers deliver intense ultrashort pulses of x-rays, which can be used to image nanometer-scale objects in a single shot. When the x-ray wavelength is tuned to an electronic resonance, magnetization patterns can be made visible. However, using increasingly intense pulses, the magnetization image fades away. The mechanism responsible for this loss in resonant magnetic scattering intensity has now been clarified.

A team of researchers from Max Born Institute Berlin (Germany), Helmholtz-Zentrum Berlin (Germany), Elettra Sincrotrone Trieste (Italy) and Sorbonne Université (France), has now precisely recorded the dependence of the resonant magnetic scattering intensity as a function of the x-ray intensity incident per unit area (the “fluence”) on a ferromagnetic domain sample. Via integration of a device to detect the intensity of every single shot hitting the actual sample area, they were able record the scattering intensity over three orders of magnitude in fluence with unprecedented precision, in spite of the intrinsic shot-to-shot variations of the x-ray beam hitting the tiny samples. The experiments with soft x-rays were carried out at the FERMI free-electron x-ray laser in Trieste, Italy.

In the results presented in the journal Physical Review Letters, the researchers show that while the loss in magnetic scattering in resonance with the Co 2p core levels has been attributed to stimulated emission in the past, for scattering in resonance with the shallower Co 3p core levels this process is not significant. The experimental data over the entire fluence range are well described by simply considering the actual demagnetization occurring within each magnetic domain, which the experimental team had previously characterized with laser-based experiments. Given the short lifetime of the Co 3p core, dominated by Auger decay, it is likely that the hot electrons generated by the Auger cascade, in concert with subsequent electron scattering events, lead to a reshuffling of spin up and spin down electrons transiently quenching the magnetization.

Read more on the ELETTRA website

Image:  Schematic sketch of the scattering experiment with two competing processes. The soft x-ray beam (blue line) hits the magnetic sample where it scatters from the microscopic, labyrinth-like magnetization pattern. In this process, an x-ray photon is first absorbed by a Co 3p core level (1). The resulting excited state can then relax either spontaneously (2), emitting a photon in a new direction (purple arrow), or by means the interaction with a second photon via stimulated emission (3). In this last case, the photons are emitted in the direction of the incident beam (blue arrow towards right). 

Synthetic fibre triumphs steel

Industrial high-strength fibre has been extensively used in daily lives. In addition to the well-known carbon fibre, “aramid fibre” has become the most comprehensive application and the largest production for the high-strength, flame retardant, and corrosion resistant fibre. Thus strong fibre is considered irreplaceable in fields such as national defense, aerospace, automotive, and energy materials. For flourishing market demand, an annual output of aramid fibre is nearly 100K tons in the word. Only several countries, including the US, Japan, Russia, and South Korean, however, are capable of mass production. Among them, the US and Japan occupy 90% market share.

Developing by DuPont company, “Kevlar” is an aramid fibre with currently the world’s leading high-strength fibre. Their strength is 5 times stronger than steel, with merely 1/5 the density of steel. In fact, the light-weight bullet proof clothing is mostly made by Kevlar.

Read more on the National Synchrotron Radiation Research Center website

Image: Customized “mini wet-spinning machine”. Credit NSRRC