Superferromagnetism with electric-field induced strain

Data storage in today’s magnetic media is very energy consuming. Combination of novel materials and the coupling between their properties could reduce the energy needed to control magnetic memories thus contributing to a smaller carbon footprint of the IT sector. Now an international team led by HZB has observed at the HZB lightsource BESSY II a new phenomenon in iron nanograins: whereas normally the magnetic moments of the iron grains are disordered with respect each other at room temperature, this can be changed by applying an electric field: This field induces locally a strain on the system leading to the formation of a so-called superferromagnetic ordered state.
Switching magnetic domains in magnetic memories requires normally magnetic fields which are generated by electrical currents, hence requiring large amounts of electrical power. Now, teams from France, Spain and Germany have demonstrated the feasibility of another approach at the nanoscale: “We can induce magnetic order on a small region of our sample by employing a small electric field instead of using magnetic fields”, Dr. Sergio Valencia, HZB, points out.

>Read more on the Bessy II at HZB website

Image: The cones represents the magnetization of the nanoparticles. In the absence of electric field (strain-free state) the size and separation between particles leads to a random orientation of their magnetization, known as superparamagnetism
Credit: HZB

Mine tailings dumped into the sea analysed with synchrotron light

The case of Portmán Bay, at the Spanish Mediterranean coast, is one of the most extreme cases in Europe causing great impact on the marine ecosystem by disposal of mine tailings.

For more than 40 years, 60 million tonnes of mine waste were dumped directly into the sea, resulting from the open pit mining that took place in Sierra Minera in Cartagena. As a consequence, the Bay was literally filled with metal-rich artificial soil. Since 2014, a research group from the University of Barcelona (UB) has been studying Portmán Bay. Now, they have analysed samples of these sediments at ALBA because with synchrotron light they can obtain unprecedented information about the heavy metals contamination, such as arsenic.

Very few people know about Portmán Bay, where took place one of the most extreme cases of coastal ecological impact by mine activity in Europe. Figures speak for itself: the mining company Peñarroya dumped more than 60 million tonnes of mine waste into the sea through a 2km-long pipeline located at the west part of the bay. Over the years, the bay became totally filled with a mountain of artificial sediment. The shoreline moved 600m seaward and the trace of the pollution reached 12km out to sea.

>Read more on the ALBA website

Image: Miquel Canals putting sample supports, which were specifically designed and printed with 3D technology at ALBA, at the CLAESS beamline to be analysed with synchrotron light; with Carlo Marini, beamline scientist and Andrea Baza, PhD student from UB.

Illuminating a key industrial process

Results of research carried out at the U.S. Department of Energy’s (DOE’s) Advanced Photon Source (APS) may pave the way to improvements in industrial processes based on solvent extraction, which is used in the mining and refinement of technologically important rare earths. The results were published in the journal Physical Review Letters.
Rare earths such as lanthanides, which are elements in the range of atomic number 57 to 71, are not actually rare. They exist in large quantities in the world, but are only found in the form of trace amounts in rocks. Since rare earths are important for a variety of applications (e.g., electronics) their extraction is a major mining-related industry.
A common process by which rare earths are extracted involves dissolving rocks in acids, then shaking up the solution with an organic solvent and a surfactant. Under the right conditions, the desired ions move out of the aqueous phase and into the organic solvent.  This is known as “liquid-liquid extraction” or “solvent extraction,” and is conducted on a large scale by the mining industry. This process also separates heavier lanthanides from lighter lanthanides present in the same solution, because the heavier lanthanides separate more easily. While this fact is known and exploited in industrial separations processes, the nanoscale mechanisms of the separation process are not well understood.

>Read more on the Advanced Photon Source

Image: (a ) Schematic of system studied; positively charged lanthanide ions (blue circles) dissolve in the water, while the negatively charged surfactant molecules (purple) float on the water surface. (b) Data showing how density of ions at the surfactant surface jumps as the concentration of ions in the bulk water increases (Er=erbium, a heavier lanthanide, Nd=neodymium, a lighter lanthanide). The lines thru data are predictions from computer simulations. From M. Miller et al., Phys. Rev. Lett. 122, 058001 (2019).

WE3 SSRL Slider

The Stanford Synchrotron Radiation Lightsource (SSRL) is one of the pioneering synchrotron facilities in the world, known for outstanding user support, training future generations and important contributions to science and instrumentation. SSRL is an Office of Science User Facility operated for the U.S. Department of Energy by Stanford University.

WE3 FERMI Slider

The program of construction and commissioning through user experiments of the FEL source FERMI, the only FEL user facility in the world currently exploiting external seeding to offer intensity, wavelength and line width stability, achieved all of its intended targets in 2017.

The ALBA synchrotron and Portugal boost their scientific collaboration

Science ministers from Portugal and Spain have visited ALBA, motivated by a collaboration agreement that promotes the Portuguese scientific community using the ALBA Synchrotron and also includes a training program for Portuguese postdoctoral researchers at ALBA.

On 11th February 2019, at the ALBA Synchrotron facility, an agreement has been signed to promote scientific collaboration between Spain and Portugal. The agreement has been signed by Caterina Biscari, director of ALBA, and Paulo Ferrão, president of the Fundação para a Ciência e a Tecnologia (FCT), under the auspices of Pedro Duque, minister of Science, Innovation and Universities of the Spanish Government, Manuel Heitor, minister of Science Technology and Higher Education of Portugal, and Àngels Chacón, regional minister of Business and Knowledge of the Catalan Government and current chair of the ALBA Rector Council.

The Portuguese scientific community has been using the ALBA Synchrotron since the beginning of its operation in 2012. Nowadays, Portugal is the 5th country that performs more experiments at ALBA, after Germany, France, Italy and the United Kingdom. They have obtained 60% of requested beamtime and have carried out experiments mainly in biology, protein crystallography and materials science.

>Read more on the ALBA website

Image: Images of the signing agreement ceremony, held at the ALBA Synchrotron. From left to right, Caterina Biscari, director of the ALBA Synchrotron, Àngels Chacón, regional minister of Business and Knowledge of the Catalan government, Pedro Duque, minister of Science, Innovation and Universities of the Spanish Government, Manuel Heitor, minister of Science Technology and Higher Education of Portugal, and Paulo Ferrão, president of the Fundação para a Ciência e a Tecnologia (FCT). In the last picture, members of the ALBA Synchrotron management, Joan Gómez Pallarés, General director of Research from the Catalan government, and Ramon Pascual, honorary president of ALBA.

2 for the price of 1: how double ionization becomes an efficient process

Double ionization is a unique mechanism where two electrons are simultaneously emitted from an atom or molecule. Typically, it’s a very weak process occurring only a few percent of the time compared to single ionization where only one electron is emitted. This is due to double ionization requiring the correlated action of two electrons hit by an energetic photon or particle. However, in a recent experiment, is has been shown that double ionization doesn’t necessarily need to be a minor effect and can even be the primary ionization mechanism.
The enhancement is likely due to double ionization proceeding through a new type of energy transfer process termed double intermolecular Coulombic decay, or dICD, for short. To experimentally observe this mechanism, dimers consisting of two alkali metal atoms were attached to the surface of helium nanodroplets. The dICD process, schematically shown in Fig. 1, occurs through an electronically excited helium atom (red), produced by synchrotron radiation, interacting with the neighboring alkali dimer (blue and white) resulting in energy transfer and double ionization. To distinguish dICD from other processes, the kinetic energies of the emitted electrons were measured in coincidence with their alkali ion counterparts.

>Read more on the Elettra website

Image: schematic view of double Intermolecular Coulombic decay (dICd).

Women in science, or welcome to everyday life at the ESRF

The 11th February, it is the International Day of Women and Girls in Science.

Today, like every other day at the ESRF, women participate in enabling the scientific progress that takes place in our institute. Meet Isabelle, Sandrine, Marie, Anne-Lise and Blanka, five of our women engineers.

Today, their work is closely related to the Extremely Brilliant Source, or EBS, the world’s first high-energy 4th generation synchrotron under construction at the ESRF. The inside of the storage ring tunnel is unrecognisable. In the short space of time since dismantling started in January, cables and cooling circuits have been disconnected and removed, and the girders and vacuum chambers lifted out. It’s a busy scene and the hundreds of different tasks involved in the dismantling is organised with almost military precision. The woman conducting the troops is Isabelle Leconte, a job she shares with colleague Pascal Renaud.

Isabelle was originally trained in chemical engineering before specialising in vacuum and cryogenic techniques. She joined the ESRF vacuum group in 1991. After 20 years developing her skills in this area, she moved to the operation group to coordinate the maintenance works during shutdown periods and follow-up machine operation and reliability. Since October last year, she has been assigned 100% to the dismantling of EBS.

>Read more on the ESRF website

Image: Marie Spitoni prepares the alignment tools on the pre-mounted girders for EBS.
Credit: ESRF/S. Candé

Enzyme structure of bacteria that causes tuberculosis

Results on its interaction with antibiotics may lead to the development of new forms of treatment for this disease.

Tuberculosis is a chronic infection usually caused by a bacterium called Mycobacterium tuberculosis. This bacterium infects cells of the immune system called alveolar macrophages, which are responsible for removing pollutants and microorganisms from the surface of the alveoli, where the exchange of gases occurs during respiration.
It is estimated that approximately two billion people worldwide are infected with M. tuberculosis without symptoms. However, the clinical manifestations of the disease may appear at any time in life, especially when the immune system is weakened, such as due to malnutrition or diseases such as cancer and AIDS.
Tuberculosis is considered a curable disease when the patient is diagnosed and treated promptly with antibiotics. Nevertheless, the chronicity of this infection makes it difficult to eradicate bacteria altogether. Generally, patients must take the medication for several months, making it harder for them to persist in the treatment and favoring the emergence of antibiotic-resistant bacteria. In recent years, the emergence of new bacteria, resistant to routine treatments, has been a worldwide concern and it is imperative to seek new therapeutic strategies against this disease.

>Read more on the Brazilian Synchrotron Light Laboratory (LNLS) 

Image: (extract, full image here) Elements of the secondary structure of L,D-transpeptidase-3 from Mycobacterium tuberculosis acylated by an acetyl fragment derived from faropenem. Beta sheets in red, α-helices in yellow and the loops are shown in green. The figure shows, at the amino terminus (N-ter), the bacterial domain similar to immunoglobulin (BIg) and in the carboxy terminus the catalytic domain (CD). B-loop is a unique structure of this enzyme when compared to the other M. tuberculosis L,D-transpeptidases. In blue is shown an acetyl fragment covalently attached to cysteine 246 at the active site of the enzyme. Figure taken with Pymol.