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

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.

Synchrotron light unveils new insights about amytrophic lateral sclerosis

Synergetic combination of different imaging and spectroscopic synchrotron techniques performed in ALBA and APS (USA) has discovered new aspects about astrocytes cells of this neurodegenerative disease.

Results, published in Analytical Chemistry, show significant differences between ALS and control astrocytes, including structural, chemical and macromolecular anomalies. Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease that causes the degeneration and death of neurons that control voluntary muscles. Still today the causes of this disease are unknown in 90% of the cases. However, some of them are caused by the mutation of sod1 gene. This gene encodes an enzyme (SOD1) that is involved in cellular protection against oxidative stress. Mutations dramatically alter the biochemical properties of SOD1, in particular its metal binding affinity and its anti-oxidative activity levels. But it is still unknown how these mutations block the normal cell function and lead to death of motor neurons. The ALBA Synchrotron, in collaboration with researchers from the University of Belgrade Pavle Andjus and Stefan Stamenković (who accomplished his PhD thesis using these results) and Vladan Lučić from Max Planck Institute of Biochemistry (Germany), has studied with synchrotron light techniques and classical biochemical laboratory approaches the cellular structural and biochemical changes of this gene mutation in a transgenic animal model of ALS. In particular, scientists have analysed astrocytes, one kind of brain cells that are key players in pathological processes of this disease.

>Read more on the ALBA website

Image: Researcher Tanja Dučić during the experiment performed at ALBA, at the MIRAS beamline.

A timely solution for the photosynthetic oxygen evolving clock

XFEL Hub collaboration reveals the intermediates of the photosynthetic water oxidation clock

A large international collaborative effort aided by the XFEL Hub at Diamond Light Source has generated the most detailed time-resolved studies to date of a key protein involved in photosynthesis. The pioneering work, recently published in Nature, shows how photosystem II harnesses light energy to produce oxygen – insights that could direct a next generation of photovoltaic cells. 
>Read more on the Diamond Light Source website

Image: this figure is issued from a video you can watch here.

ESRF celebrates 30 years of science, 30 years of international collaboration

The ESRF celebrates its 30th anniversary in the presence of the representatives of its 22 partner countries. This event looks back at ESRF’s scientific accomplishments but also on the role that the ESRF has played in fostering peaceful cross-border collaboration in Europe and beyond.

“Congratulations on 30 years of success; here is to 30 more to come,” said Carlos Moedas, European Commissioner for Research, Science and Innovation, in a video message.

“ESRF is a shining example of what can be achieved when people of different nationalities and cultures come together to pursue a common goal, to push back the frontiers of science,” said ESRF Director General Francesco Sette. “In drawing up the ESRF Convention, back in 1988, the ESRF’s founding fathers established a unique model for scientific and technological excellence. Today, with 22 partner countries, and by bringing together scientists from all over the world, the ESRF continues to demonstrate how science unites nations and contributes to addressing complex global challenges facing our society.”

2018 holds a particular significance for the ESRF as the facility celebrates its 30th anniversary. In 1988, 11 countries joined forces to create the first third-generation synchrotron light source: a dream became a reality. Thirty years later, the ESRF has broken records for the brilliance and stability of its X-ray beams, for its scientific output (over 32 000 publications, i.e., around 2 000 publications per year during the last ten years, and four Nobel prize laureates), and for the strength of its community of users (about 10 000 scientific visits per year with users from 50 different countries).

>Read more on the European Synchrotron (ESRF) website

 

From Pakistan to Barcelona, from scientists to friends

Shamila Imtiaz and Sidra Ibadat happily describe their experience during their research internship at ALBA within the framework of the Open Sesame European project.

Shamila Imtiaz (31 years old, PhD candidate and Chemistry junior scientist at PINSTECH Islamabad) and Sidra Ibadat (25 years old, MS Physics Student at the International Islamic University Islamabad) happily describe their experience during their research internship at ALBA. They come from Pakistan and have been granted by the H2020 Open Sesame project to spend 8 weeks at our facility in order to widen their expertise in synchrotron-based Fourier Transform Infrared Microspectroscopy SR-FTIRM at the infrared beamline MIRAS. For both of them, this is their first experience in Europe and, apart from their scientific activity, they are enjoying their walks, their talks and taking care of Shamila’s 9-month old baby. Additionally, ALBA is “proud to help in the development of the scientific careers of young mothers here and elsewhere”, says Miguel Ángel García Aranda, ALBA Scientific Director

“The situation in Pakistan has greatly changed in the past years, there are more women than men in science studies but it’s not easy to find funding opportunities to continue with the studies”, says Sidra. “The Open Sesame project has been a great opportunity for us for visiting and seeing how a synchrotron light source works and bring back all this knowledge to our country”, according to Shamila. “Having access to more sophisticated tools that those in Pakistan can boost our research projects”, continues Sidra.

>Read more on the ALBA website

HZB builds undulator for SESAME in Jordan

The Helmholtz-Zentrum Berlin is building an APPLE II undulator for the SESAME synchrotron light source in Jordan. The undulator will be used at the Helmholtz SESAME beamline (HESEB) that will be set up there by five Helmholtz Centres. The Helmholtz Association is investing 3.5 million euros in this project coordinated by DESY.
SESAME stands for “Synchrotron Light for Experimental Science and Applications in the Middle East” and provides brilliant X-ray light for research purposes. The third-generation synchrotron radiation source became operational in 2017. Egypt, Iran, Israel, Jordan, Pakistan, the Palestinian Authority, Turkey, and Cyprus are cooperating on this unique project to provide scientists from the Middle East with access to one of the most versatile tools for research.

New beamline for soft x-rays

Thus far, SESAME has four beamlines and will now receive a fifth meant to generate “soft” X-ray light in the energy range between 70 eV and 1800 eV. This X-ray light is particularly suitable for investigating surfaces and interfaces of various materials, for observing certain chemical and electronic processes, and for non-destructive analysis of cultural artefacts. The new beamline will be constructed as the Helmholtz SESAME Beamline (HESEB) by the Helmholtz Centres DESY (coordinating Centre), Forschungszentrum Jülich, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Helmholtz-Zentrum Berlin (HZB) as well as the Karlsruhe Institute of Technology (KIT).

>Read more on the Bessy II at HZB website

Image: The APPLE II UE56 double undulator generates brilliant light with variable polarization.
Credit: HZB

LEAPS holds its first plenary meeting

Synchrotron radiation source SESAME welcomed as associated partner

On 12 and 13 November, the League of European Accelerator-based Photon Sources (LEAPS), the association of European research lightsources, met at DESY for its first plenary meeting. More than 150 scientists from the 16 accelerator-based lightsources in Europe, which are members of LEAPS, travelled to Hamburg to do so. Among them were the directors of all institutions, representatives of eight national science ministries and research funding agencies as well as Philippe Froissard from the European Commission.
“The League of European Accelerator-based Photon Sources has made great progress since its foundation a year ago, and I am convinced that this is the way to make our science with European lightsources shine even brighter in the future,” said Helmut Dosch, Chairperson of LEAPS, who opened the meeting together with LEAPS Vice-Chairperson Caterina Biscari from the Spanish synchrotron radiation source ALBA. The LEAPS consortium represents the interests of more than 25 000 users in total.
>Read more on the DESY website
and another article on the ALBA website. Please find here all news about the LEAPS initiative.

SESAME becomes the first associate of LEAPS

At its first Plenary Meeting that is being held at DESY on 12-14 November, the Members of LEAPS (League of European Accelerator-Based Photon Sources) unanimously decided to grant SESAME Associate status.

SESAME thus becomes the first Associate of LEAPS.

On signing the Declaration of Association to the LEAPS Consortium with Helmut Dosch, Chair of LEAPS and Chair of the DESY Board of Directors, Rolf Heuer, President of the SESAME Council, said that “it is a great honour for SESAME to be the first Associate of LEAPS; the scientific and technical development of SESAME and visibility of the Centre will greatly benefit from this association”.

>Read more on the SESAME website

Image: Schematic overview from SESAME, find more here.

Ferroelectric control of the spin texture in GeTe

Spin-orbit coupling effects in materials with broken inversion symmetry are responsible for peculiar spin textures, giving rise to intriguing phenomena such as intrinsic spin Hall effect. Among these materials, ferroelectrics allow for non-volatile control of the spin degree of freedom through the electrical inversion of the spin texture, based on their reversible spontaneous polarization. Finding suitable ferroelectric semiconductors would be a fundamental achievement towards the implementation of novel electronic and spintronic devices combining memory and computing functionalities.
Germanium Telluride emerges as promising candidate, since theoretically proposed as the father compound of the new class of ferroelectric Rashba semiconductors. Its ferroelectricity provides a non-volatile state variable able to generate and drive a giant bulk Rashbatype spin splitting of the electronic bands. Its semiconductivity and silicon-compatibility allows for the realization of spin-based non-volatile transistors.
A European team of both experimentalists and theoreticians from Italy (Politecnico di Milano, IFN-CNR, CNR-SPIN, CNR-IOM) and Germany (Paul-Drude-Institut für Festkörperelektronik, Universität Würzburg) has demonstrated the ferroelectric control of the Rashba spin texture in GeTe probed by spin and angular resolved photoemission spectroscopy at the Advanced Photoelectric Effect experiments (APE) beamline and supported by NFFA.

>Read more on the Elettra Sincrotrone Trieste website

Image: (a, a’) PFM ferroelectric hysteresis loops and the pristine polarization states for the as-prepared Te- and Ge-terminated GeTe(111) surfaces, respectively. (b, b’) DFT calculations of the k-resolved spin polarization along two high symmetry crystallographic directions. The main bulk Rashba bands are marked as B1 and B2. The black dashed line indicates the wave vector k of SARPES measurements. (c, c’) Spin-polarized currents and spin asymmetries (Px) versus binding energy at the wave vector k. The peaks correspond to the intersection of the Rashba bands B1 and B2 with the vertical dashed line at k. (d, d’) Constant energy maps for the Te- and Ge-terminated surfaces. Blue and red arrows indicate the sense of circulation of spins, opposite for the two opposite ferroelectric polarizations.

Acid-base equilibria: not exactly like you remember in chemistry class

Work published in the Royal Society of Chemistry with the support of the Helmholtz Association through the Center for Free-Electron Laser Science at DESY, MAX IV Laboratory, Lund University, Sweden,  European Research Council (ERC) under the European Union’s Horizon 2020 and the Academy of Finland.

Remember doing titrations in chemistry class? Adding acid drop-by-drop to the beaker and the moment you took your eye off it the solution completely changed colour.
We learned in chemistry that by doing this titration, we were actually affecting an important equilibrium in the beaker between acids and bases. This equilibrium was first described at the turn of the 20th century by American biochemist Lawrence Henderson and modified by Karl Hasselbalch giving us the Henderson-Hasselbalch equation. The discovery and subsequent study of acids and bases using this equation has led to the discovery of many important phenomena in the natural world from as how cells function to how materials are formed.

However, after years of study, an idea arose that questioned the validity of the Henderson-Hasselbalch equation, what happens at the surface? If you have a beaker filled with a dilute acid, what happens at the very top atomic layer? The top layer of a liquid in a beaker is special for many reasons, but if you’re a dissolved molecule, it means that you’re no longer surrounded by water on all sides. For hydrophobic molecules, this means that it is favourable to be at the surface. With this in mind, the scientists took another look at the Henderson-Hasselbalch equilibrium equation and thought that it couldn’t work at the surface. Many studies have measured indicator chemical species, and determined that the Henderson-Hasselbalch equation does not seem to apply at the surface, and concluded that the concentration of hydronium or hydroxide ions, which determines the acidity/basicity, is different at the air-liquid interface than in the bulk.

>Read more on the MAXIV Laboratory website

 

 

Steering the outcome of photoionization in a molecule

An important step towards the understanding and control of photoinduced fragmentation processes in molecules has been achieved in an experiment on the H2 molecule taking advantage of the unique properties of the FERMI free-electron laser source in the vacuum ultraviolet (VUV) photon energy range.
Molecular dissociation, i.e., the breaking of a chemical bond, is governed by the coupling of electronic and nuclear motion and, once understood and controlled in large systems, e.g., by utilizing ultrashort light pulses, has the potential to impact tremendously photochemical and biochemical applications. A team of both experimentalists and theoreticians from France (CNRS, Université Paris-Sud, Université de Bordeaux), Spain (Universidad Autónoma de Madrid), Germany (European XFEL), and Italy (Elettra-Sincrotrone Trieste) has demonstrated that the outcome of dissociative (DI) and nondissociative (NDI) photoionization in the simplest of all molecules, H2, can be controlled exploiting nonlinear two-photon ionization with intense femtosecond pulses in the VUV.
The FERMI seeded free-electron laser is currently the only light source worldwide that provides external users access to bright femtosecond pulses at wavelengths in the VUV up to 100 nm, the energy regime required for studying nonlinear two-photon single-ionization in H2. The high spectral resolution and precise tunability of the 100-fs pulses provided by FERMI made it possible to selectively excite single vibrational levels in the neutral intermediate B state of H2 (blue line in Fig. 1). Absorption of a second VUV photon then leads to NDI or DI into the ionic H2+ ground state (green in Fig. 1) or to DI into the first excited H2+2p continuum (orange in Fig. 1). In single-photon single-ionization of H2, the yield of DI is very low – less than 2%. By contrast, recent ab initiocalculations suggest that the ratio of DI/NDI can be increased significantly in resonance-enhanced two-photon ionization and that it can be controlled by varying the pulse duration between 2 and 10 fs.

>Read more on the Elettra website

Image: (a) Schematic of resonant two-photon ionization viathe B intermediate state (12.51 eV). The grey shaded area shows the Franck-Condon region for one-photon absorption from the H2electronic ground state. The dashed purple arrows visualize the range for the absorption of the second FEL photon. The green (red) horizontal line shows the ionization threshold at 15.43 eV (dissociation limit at 18.08 eV). (b) The experimental photoelectron spectrum shows a clear separation of electrons correlated to NDI and DI. For DI, it is close to the prediction of the Condon-reflection approximation, i.e., the projection of the vibrational wavefunction onto the dissociative 2p continuum state. The infinite-time limit calculation (grey line for the convolution of the contributions from the two first ionization continua) reproduces the main features of the spectrum. The differences between experiment and calculation indicates that at FERMI a timescale between ultrafast dynamics and steady-state excitation is probed.

Research on ancient teeth reveals complexity of human evolution

Fossil records enable a detailed reconstruction of our planet’s history and of the evolution of our species. In particular, teeth are a sort of biological archive that record in their structures (enamel, dentine and pulp chamber) the different phases of the human evolution. An international team of researchers led by Clément Zanolli from the Université Toulouse III Paul Sabatier (France) has characterized human dental remains from Fontana Ranuccio (Latium) and Visogliano (Friuli-Venezia Giulia), Italy through a comparative high-resolution endostructural analysis based on microfocus X-ray microtomography (mCT) scanning and detailed morphological analyses. We examined the shape and arrangement of tooth tissues (see Fig. 1) and compared them with teeth of other human species (see Fig. 2).

With an age of around 450,000 years before present, the analysed dental remains from the sites of Fontana Ranuccio, located 50 km south-east of Rome, and Visogliano, located 18 km north-west of Trieste, are part of a very short list of fossil human remains from Middle Pleistocene Europe and are among the oldest human remains on the Italian Peninsula.
From the data obtained through X-ray μ-CT measurements performed at the TomoLab station of Elettra and at the Multidisciplinary Laboratory of the ‘Abdus Salam’ International Centre for Theoretical Physics in Trieste (Italy), we found that the teeth of both sites share similarities with Neanderthals but they are distinct from modern humans. This study adds to an emerging picture of complex human evolution in Middle Pleistocene Eurasia.  The investigated fossil teeth show that Neanderthal dental features had evolved by around 450,000 years ago.

>Read more on the Elettra Sincrotrone Trieste website

Image: Volume rendering of the Fontana Ranuccio (FR1R and FR2) and Visogliano (Vis. 1-Vis. 6) tooth specimens. The enamel is represented in blue while the dentine in yellow. All specimens were imaged by X-ray μCT at the Tomolab station of Elettra and at the Multidisciplinary Laboratory of the ICTP.     
Credit:  doi: 10.1371/journal.pone.0189773

Molluscs use thermodynamics to create complex morphologies with exceptional properties

An international team has found how some molluscs create their complex structures.

Their work provides new tools for novel bioinspired and biomimetic bottom-up material design.
Nature serves as a source of inspiration for scientists and engineers thanks to the complex material architectures that make up some living organisms. These materials carry out essential functions, ranging from structural support and mechanical strength, to optical, magnetic or sensing capabilities. One example of this are molluscan shells, made of mineralized tissues organised in mineral-organic hierarchical functional architectures.

Molluscs appeared more than 500 million years ago, and they have developed hard and stiff mineralised outer shells for structural support and protection against predation. Their shells consist of mineral-organic composite structures made of calcium carbonates, mostly calcite and aragonite. The different shells exhibit a large variety of intricate three-dimensional assemblies with superior mechanical properties.

>Read more on the European Synchrotron website

Italy now European XFEL shareholder

On Friday 5 October, the Italian research organisations INFN and CNR officially became shareholders of European XFEL GmbH.

The National Institute for Nuclear Physics (INFN) and the National Research Council (CNR) together now own 2.9% of the company’s shares; one third going to INFN and two thirds to CNR. Italy has been a European XFEL partner country since the foundation of the company. With the acquisition of the shares, INFN and CNR – both designated by Italy as Italian shareholders – now also have full voting rights in the company’s supreme organ, the European XFEL Council. The Italian share of 2.9% in the company corresponds to the Italian contributions to the total European XFEL construction and operation budgets, making Italy the fourth largest funders following Germany, Russia, and France.

>Read more on the European XFEL website

Image: Representatives from DESY, European XFEL, INFN and CNR celebrate after the signing of the accession documents today. From left to right: Veronica Buccheri, INFN; Nicole Elleuche, European XFEL; Roberto Pellegrini, INFN; Rosario Spinella, CNR; Bruno Quarta, INFN; Reinhard Brinkmann, DESY; Robert Feidenhans’l, European XFEL; Christian Harringa, DESY.
Credit: European XFEL

Diamond shines its light on moon rocks

Nearly 50 years after our first steps on the Moon, rock samples from the Apollo missions still have a lot to tell us about lunar formation, and Earth’s volcanoes.

An international collaboration involving scientists in Tenerife, the US and the UK, are using Diamond, the UK’s national synchrotron light source, to investigate Moon rocks recovered during the Apollo Missions in a brand new way.
Dr. Matt Pankhurst of Instituto Volcanológico de Canarias and NASA lunar principle investigator explains: “We have used a new imaging technique developed at Diamond to carry out 3D mapping of olivine – a common green mineral found in the Earth’s sub-surface and in these Moon rock samples. These maps will be used to improve understanding of the Moon’s ancient volcanic systems and help to understand active geological processes here on Earth.
With this new technique, our team may be able to recover from these Moon rock samples information such as what the patterns of magma flow within the volcanic system were, what the magma storage duration was like, and potentially even identify eruption triggers. The data will be analysed using state-of-the-art diffusion modelling which will establish the history of individual crystals.”

>Read more on the Diamond Light Source website

Image:
Dr Matt Pankhurst studies one of the moon rock samples from the Apollo 12 & 15 missions at Diamond Light Source