Category: ALBA

Revealed: 3D magnetic configuration of ferrimagnetic multilayers with competing interactions

Revealed: 3D magnetic configuration of ferrimagnetic multilayers with competing interactions

Researchers from the Physics Department of the Universidad de Oviedo, CINN-CSIC and HZB, in collaboration with ALBA, have explored the magnetic configuration of ferrimagnetic structures often employed to build modern spintronic devices and magnetic recording media. At the MISTRAL beamline of ALBA, using vector magnetic tomography, a magnetic trilayer fabricated at Oviedo was characterized. These findings will permit to generate precise physical models describing the magnetic behaviour of this type of systems and control and exploit them for the design of spintronics and magnetic storage devices.

 Modern spintronic devices and magnetic recording media often consist of complex magnetic structures. These structures are designed by precisely adjusting magnetic interactions as exchange, anisotropies and magnetostatics to achieve specific characteristics.

A collaboration between researchers from the Physics Department of the Universidad de Oviedo, the Centro de Investigación en Nanomateriales y Nanotecnología (Oviedo), the Helmholtz Zentrum Berlin für Materialien und Energie (Berlin) and the ALBA Synchrotron have investigated a combination of ferrimagnetic structures, often employed to build this type of devices. 

At the MISTRAL beamline of ALBA, a dichroic vector magnetic tomography of the device was performed and it revealed details of complex magnetisation configurations of the sample. The importance of synchrotron light lies in the fact that this information is currently impossible to evidence with other techniques when studying magnetic thin films.

The ability to characterize the configuration of the magnetisation in complex structures with competing magnetic interactions will permit to generate precise physical models describing the magnetic behaviour of these systems. Thus, experts will be able to control and exploit them for the design of spintronics and magnetic storage devices.

Read more on the ALBA website

Image: Magnetisation obtained from the magnetic tomography data at the MISTRAL beamline.

Cyborg plants: roots can store energy

Cyborg plants: roots can store energy

Researchers of the HyPhOE European Project have developed biohybrid plants with an electronic root system, which could be used to store energy or as electronic sensors. This study proved the integration of circuits and electrochemical devices into the plants without damaging them, so that they continued to grow and adapt to their new hybrid state. Experiments at the NCD-SWEET beamline of the ALBA Synchrotron were crucial to shed light on the plant-based technology field.

Plants are amazing machines: not only they are solar-powered and convert carbon dioxide into chemical energy, but they are also capable of producing cellulose, the most abundant biopolymer on Earth, and can self-repair via tissue regeneration. All these factors make plants the perfect candidates for developing biohybrid technological systems, integrating smart materials and devices into their structure.

In a recent publication, the team led by researcher Eleni Stavrinidou from the Linköping University (Sweden) has presented a study about biohybrid plants with an electronic root system. They found out how to integrate circuits and electrochemical devices into the plants without damaging them, so that they can continue to grow and develop, and use them as supercapacitors or electronic sensors.

The results pave the way for using roots for energy storage and the creation of a root-based supercapacitor. Supercapacitors based on conductive polymers and cellulose offer an environmentally friendly alternative for energy storage that may also be more affordable than those currently in use. As a proof of concept, the research team built a supercapacitor where the roots served as the charge storage electrodes.

Another possible application of these plant-based systems are electronic sensors. For example, by adding a humidity sensor in the root, the information could be transmitted through the electronic root network to an intelligent system, which could act accordingly by increasing or decreasing the frequency of irrigation. These discoveries open the door to new intelligent stimulus-response applications.

This study is part of the European project Hybrid Electronics Based on Photosynthetic Organisms (HyPhOE), which involves several European institutions and aims to achieve a symbiosis between photosynthetic organisms and technology.

Read more on the ALBA website

Image: Bean plant before, during and after functionalization

Promising new extra-large pore zeolite

Promising new extra-large pore zeolite

An international research team, led in Spain by CSIC scientist Miguel A. Camblor, has discovered a stable aluminosilicate zeolite with a three dimensional system of interconnected extra-large pores, named ZEO-1.

Zeolites are crystalline porous materials with important industrial applications, including uses in catalytic processes. The pore apertures limit the access of molecules into and out of the inner confined space of zeolites, where reactions occur.

The research, published in Science, proved that ZEO-1 possesses these “extra-large” pores of around 10 Å (1 angstrom equals one ten billionth of a meter), but also smaller pores of around 7 Å, which is actually the size of traditional “large” pores.

Because of its porosity, strong acidity and high stability, ZEO-1 may find applications as a catalyst in fine chemistry for the production of pharmaceutical intermediates, in controlled substance release, for pollution abatement or as a support for the encapsulation of photo- or electroactive species (they react to light or an electric field).

“The crossings of its cages delimit super boxes, open spaces that can be considered nanoreactors to carry out chemical reactions in their confined space”, explains Miguel A. Camblor, researcher at the Instituto de Ciencia de Materiales de Madrid – CSIC.

To prove that this new zeolite may be useful in applications involving bigger molecules, researchers measured the adsorption to the inner surface of the zeolite of the dye Nile red – a big molecule. Moreover, they tested its performance in fluid catalytic cracking of heavy oil, a process the world still relies on to produce fuels. In both processes, the new zeolite performed better than the conventional large pore zeolite used nowadays.

This research is the result of an international collaboration between eight research centers in China, the USA, Sweden and Spain. The team was led by Fei-Jian Chen (Bengbu Medical College, China), Xiaobo Chen (China University of Petroleum), Jian Li (Stockholm University) and Miguel A. Camblor (Instituto de Ciencia de Materiales de Madrid, CSIC).

Structure determination with synchrotron light

The zeolite was discovered following a high-throughput screening methodology. The structure solution was challenging because the zeolite has a very complex structure, with a small crystal size (<200nm) but an exceedingly large cell volume.

“The combination of electron diffraction data with synchrotron powder X-ray diffraction data collected at the MSPD beamline of the ALBA Synchrotron and the Argonne National Laboratory (USA) made possible the accurate structure determination of ZEO-1″, says Camblor.

Read more on the ALBA website

Image: A perspective view of the extra-large pore of ZEO-1 along (100)

Crossing the border for understanding how life is assembled

Crossing the border for understanding how life is assembled

Ana’s #LightSourceSelfie from the ALBA synchrotron in Spain

Ana Joaquina Pérez-Berná is a beamline scientist at the ALBA synchrotron near Barcelona in Spain.

As a biologist working on the soft X-ray cryo tomography beamline (MISTRAL), her role involves supporting the users with their experiments and also doing her own research. The beamline’s capabilities enable scientists to study down at the cellular level and the research covers a wide variety of diseases such as malaria, zika virus and SARS-CoV-2, along with treatments such as antivirals and chemotherapy. When describing her work, Ana says, “You are the first person who can enter the cell and see how it is inside, discover how the virus builds its bio-factories inside the cells, or discover how therapies work. Crossing that border for understanding how life is assembled, that is a privilege!”

Differences between African, Caucasian and Asian Hair

Differences between African, Caucasian and Asian Hair

Researchers of IQAC-CSIC, in collaboration with the ALBA Synchrotron, demonstrate that African hair has more lipids that are highly disordered. This distinction with Caucasian and Asian hair might be relevant to develop new ethnic hair-care products.

Cerdanyola del Vallès, 14th December 2021Researchers from the Institute for Advanced Chemistry of Catalonia (IQAC-CSIC) in collaboration with the ALBA Synchrotron have studied and compared the lipid distribution of African, Caucasian and Asian hair fibers. More specifically, the work has determined the presence, distribution, and function of lipids of each ethnicity. The differences observed can explain some of the barrier properties against external substances that each hair type presents. In particular, African hair was demonstrated to have more lipids that are highly disordered, which can explain its differentiation from Asian and Caucasian hair concerning moisturization and swelling (when water content inside the fiber increases).

Read more on the ALBA website

Image: Left: Cross-sections observed by optical microscopy for Caucasian hair selected to analyze by μ-FTIR, regions were manually determined. Right: Chemical map of second derivative obtained at 2850 cm−1 (CH2 symmetric stretching) of Caucasian virgin hair (a) and Caucasian delipidized hair (b).

Credit: ALBA

Novel protocol for mass production of nanowires

Novel protocol for mass production of nanowires

Nanotechnology is one of the major driving forces behind the technological revolution of this century and nanomaterials play a key role in this revolution. While the use of nanoparticles is widespread in industrial applications, the use of nanowires -wires with a diameter of only a few nanometres- is mostly reduced to scientific areas. The fields of biomedicine and permanent magnets would benefit from the cost-effective mass production of nanowires.

In a recent publication, researchers from the Universidad Complutense de Madrid (UCM) and various centres from the Consejo Superior de Investigaciones Científicas (CSIC), in collaboration with ALBA, have established a novel and sustainable synthesis protocol that allows obtaining a greater number of nanowires than conventional laboratory fabrication processes with considerably reduced production time and cost.

The goal of this project was to increase the production of metallic nanowires, reducing costs and timings to expand their applicability to industry. Due to the high costs associated with the high-purity aluminium normally used as the starting material, as well as with the low temperature and large anodization time, the commercial application of nanowires using anodized aluminium oxide is still limited by their fabrication process.

Read more on the ALBA website

Image: The CIRCE beamline (variable polarization soft X-ray beamline dedicated to advanced photoemission experiments)

Credit: ALBA

Spintronics: Exotic ferromagnetic order in two-dimensions

Spintronics: Exotic ferromagnetic order in two-dimensions

An international team has detected at HZB’s vector magnet facility VEKMAG an unusual ferromagnetic property in a two-dimensional system, known as “easy-plane anisotropy”. This could foster new energy efficient information technologies based on spintronics for data storage, among other things. The team has published its results in the renowned journal Science.

The thinnest materials in the world are only a single atom thick. These kinds of two-dimensional or 2D materials – such as graphene, well-known as consisting of a single layer of carbon atoms – are causing a great deal of excitement among research teams worldwide. This is because these materials promise unusual properties that cannot be obtained using three-dimensional materials. As a result, 2D materials are opening the door to new applications in fields such as information and display technology, as well as for critical components in extremely sensitive sensors.

Read more on the HZB website

Image: STM topography of a monolayer CrCl3 grown on Graphene/6H-SiC(0001). Inset, a magnified topography image, which reveals the grain boundaries.

Credit: HZB

Silver nanoparticles for the elimination of ammonia released to the atmosphere

Silver nanoparticles for the elimination of ammonia released to the atmosphere

Researchers from the ITQ-UPV-CSIC, in collaboration with ALBA, have explored the use of silver nanoparticles as catalysts for the selective catalytic oxidation of ammonia, one of the main atmospheric pollutants. Thanks to the CLÆSS beamline at ALBA, researchers proved that the active catalyst for the reaction of ammonia to nitrogen and water is metallic silver, instead of silver cations. These findings will contribute to developing new methods for the elimination of ammonia released to the atmosphere in industry and in diesel vehicles.

Ammonia is one of the main atmospheric pollutants and damages both the human health and the environment. Most ammonia emissions come from fertilizers used in agriculture, but it is also released to the atmosphere in biomass burning, fuel combustion and industrial processes, in which unreacted ammonia escapes into the atmosphere in the exhaust gases.

In the last years, more strict environmental regulations have been intensified with the aim to develop new methods for the elimination of this pollutant. The most promising technology is the selective catalytic oxidation of ammonia to nitrogen and water.

In a recent publication, researchers from the Instituto de Tecnología Química, Universitat Politècnica de València – Consejo Superior de Investigaciones Científicas (UPV-CSIC), in collaboration with ALBA, have explored the use of silver-containing zeolites (microporous aluminosilicates) for the catalytic oxidation of ammonia. Results confirmed that the active site for the reaction is the silver found in the form of metallic nanoparticles at the external surface of the zeolite, whereas silver cations (Ag+)are practically non-active.

Furthermore, the experiment proved that silver nanoparticles present in the active catalyst were dispersed and oxidized to silver cations during the reaction. These findings will allow the scientific community to develop a method for removing ammonia released to the atmosphere in industry and in diesel vehicles.

The experiment, performed at the CLÆSS beamline in the ALBA Synchrotron, allowed to study the catalysts under reaction conditions. The researchers recorded several X-ray absorption spectra (XAS) while submitting the samples to the reactive atmosphere (ammonia and oxygen) at increasing temperatures. Results showed that the silver nanoparticles formed before the reaction were dramatically modified under reaction conditions, being most of them dispersed and resulting in small clusters and cations Ag+.

Read more on the ALBA website

Image: NH3-SCO reaction pathway using Ag-Zeolites

Metal pollutants cause metabolic alterations in algae

Metal pollutants cause metabolic alterations in algae

Contamination by metals like cadmium or mercury is considered a serious threat to the environment and human health. Several human activities such as mining, metallurgy industry, and extensive use of mineral fertilizers are the main sources of ongoing metal pollution in numerous ecosystems. This environmental risk is potentiated by bioaccumulation and trophic chain biomagnification phenomena, which are associated with the long persistence of toxic metals in the polluted ecosystems. Aquatic and soil ecosystems affected by runoffs loaded with toxic metals are particularly vulnerable, where primary producers photosynthetic organisms (phytoplankton and soil microalgae) represent the first stage of pollution build-up. Knowledge about mechanisms of toxicity in these organisms is essential for appropriate assessment of environmental risks.

Researchers from the Plant Physiology Laboratory of the Department of Biology, also affiliated with the Research Centre for Biodiversity and Global Change, at the Autonomous University of Madrid (UAM), have discovered the major changes of biomolecules caused by cadmium and mercury in the model green microalga Chlamydomonas reinhardtii.

The use of synchrotron technology at MIRAS beamline was a valuable tool and has made it possible to analyze in detail variations in the biomolecular pattern caused by heavy metals at levels of resolution rarely described before. “Among the cellular components that readily changed upon metal treatments, we detected alterations in the lipid composition by synchrotron light infrared spectroscopy at ALBA, which corresponded to accumulation of neutral lipids and increased fatty unsaturation” specifies Ángel Barón, scientist at UAM.

Read more on the ALBA website

Image: Electron transmission microscopy of Chlamydomonas reinhardtii cells to show alterations caused by cadmium and mercury. The pyrenoid (p) looks aberrant, with proliferation of lipid vesicles (green arrowhead) and starch grains (s). Metals also triggered the appearance of autophagy vesicles (red arrowhead). Right: image of Chlamydomonas reinhardtii 

Credit: image of Chlamydomonas reinhardtii  Wikimedia Commons.

Tuning the magnetic anisotropy of lanthanides

Tuning the magnetic anisotropy of lanthanides

The magnetism of lanthanide-directed nanoarchitectures on surfaces can be drastically affected by small structural changes. The study carried out in a collaboration between researchers from IMDEA Nanociencia and BOREAS beamline at ALBA reports the effect of the coordination environment in the reorientation of the magnetic easy axis of dysprosium-directed metal-organic networks on Cu(111). The authors show that the magnetic anisotropy of lanthanide elements on surfaces can be tailored by specific coordinative metal-organic protocols.

Recent findings have highlighted the potential of lanthanides in single atom magnetism. The stabilization of single atom magnets represents the ultimate limit on the reduction of storage devices. However, single standing atoms adsorbed on surfaces are not suitable for practical applications due to their high diffusion, i.e., low thermal stability. The next step towards more realistic systems is the coordination of these atoms in metal-organic networks.In 4f elements, the spin-orbit coupling (SOC) is larger than the crystal field, which might result in higher anisotropies. Furthermore, the crystal field acts as a perturbation of the SOC and can be tailored to increase the anisotropy by choosing an appropriate coordination environment. The strong localization of the 4f states reduces the hybridization with the surface, increasing the spin lifetimes, which is crucial, since a long magnetic relaxation time is mandatory for technological applications.

Read more on the ALBA website

Image: Cover picture showing the structure of the Dy-TPA network where C, H, O and Dy atoms are represented by black, red and green balls, respectively, the tilted orientation of the magnetic easy axis is represented by green arrows. 

Credit: ALBA

A new way of controlling skyrmions motion

A new way of controlling skyrmions motion

A group of researchers from France has been able to create and guide skyrmions in magnetic tracks. These nanoscale magnetic textures are promising information carriers with great potential in future data storage and processing devices. Experiments at the CIRCE-PEEM beamline of the ALBA Synchrotron enabled to image how skyrmions move along tracks written with helium ions.

Magnetic skyrmions are local twists of the magnetization, considered as units (bits) in new magnetic data storage devices. They were named after British physicist Tony Hilton Royle Skyrme, who described these whirling configurations in the 80’s. But it was not until 2006 that there was evidence of their existence.

Skyrmions are of great interest for the scientific and industrial community as they could help finding more efficient ways to store and process information in our computers. They can be manipulated with lower electrical currents, opening a path for being used as information carriers.

But skyrmions are difficult to control. They do not move in straight lines when current is injected but naturally drift sideways, “killing” themselves. This is known as the Skyrmion Hall effect. In order to be used in devices, they need to be moved and controlled in a reliable way.

A group of researchers led by Olivier Boulle from SPINTEC (Grenoble, France) has a wide experience on the subject. They already reported in 2016 the first observation of magnetic skyrmions under conditions appropriate to the industrial needs, with experiments done at the ALBA Synchrotron.

Now, they have found a way to create and guide skyrmions in racetracks: by irradiating magnetic ultrathin layers with helium ions. This method enables to locally tune the magnetic properties to the desired point without introducing defects in the layer.

The samples were prepared and its magnetic properties were locally modified by helium ions irradiation to create the tracks. Later, they were characterized with different techniques to ensure the preparation was consistent. At the CIRCE beamline of the ALBA Synchrotron, using the PEEM photoemission electron microscope, they were able to image how skyrmions move along the tracks when receiving current pulses. Results were confirmed with magnetic force microscopy and micromagnetic simulations.

Read more on the ALBA website

Image: Micromagnetic simulation showing skyrmion motion along the irradiated racetrack. The irradiated racetrack confines the skyrmions within and they move with nanosecond (ns) current pulses along the track edge without being annihilated, thereby deminishing the Skyrmion Hall Effect (SkHE) (current densities in the parentheses are in A.m-2).

Researchers discover the origin of calcium in human bones

Researchers discover the origin of calcium in human bones

A study from several Italian institutions and the ALBA Synchrotron suggest crystalline calcium carbonate as a precursor of hydroxyapatite in the process of bone formation. Since hydroxyapatite is a mineral constituting 70% of the mass of bone, these findings may have potential applications in the development of new therapeutic approaches in bone cancer. Thanks to the MISTRAL beamline at ALBA, researchers were able to create a 3D tomogram of human cells and visualize calcium depositions inside them.

Stem cells are “non-specialized” cells that can differentiate (transform) into a specific type of cell with a specific function. To become bone cells, stem cells need to “learn” how to take calcium to form the bones. This is related to biomineralization, a process by which living organisms produce minerals, often to harden or stiffen existing tissues. Calcium is known to be found in bones in the form of hydroxyapatite, which is a naturally occurring mineral form of calcium apatite and represents approximately 70% of the mass of bones.

In human cells, biomineralization culminates with the formation of hydroxyapatite, but the mechanism that explains the origination inside the cell and the propagation of the mineral in the extracellular matrix remains largely unexplained, and its characterization is highly controversial, especially in humans.

An interdisciplinary research team, formed by several Italian institutions and the ALBA Synchrotron, used synchrotron-based techniques to characterize the contents of calcium depositions in human stem cells induced to differentiate towards bone cells (osteoblasts). They compared the results for cells at 4 and 10 days after the osteoblastic induction.

Rad more on the ALBA website

Image: Model of early phases of biomineralization showing the localization and composition evolution of Ca compounds during the early phases of osteogenic differentiation. The figure reports also the spectra of Calcite and hydroxyapatite.

Unravelling the history of 15th Century Chinese porcelains

Unravelling the history of 15th Century Chinese porcelains

Researchers from French and Spanish Institutions used the combination of two synchrotron light characterization techniques to study Chinese blue-and-white Ming porcelains. They were able to identify the firing temperature by determining the porcelain’s pigments and the reduction-oxidation media conditions during their production. The approach they used can also be applied on a broad range of modern and archaeological ceramics to elucidate their production technology.

Pottery is found at the majority of archaeological sites dating from the Neolithic period, when first human settings appear, onwards. Which makes it a major focus of study in archaeological science.  The study of style and production of ceramics is central to the historical reconstruction of a site, region and period.

More specifically, ceramic technological studies look to reconstruct the production technology of ceramics, by determining the selection and preparation of the raw materials, the formation of ceramics, treatment and decoration of the ware’s surface and the firing atmosphere. All of this is possible thanks to the scientific techniques available nowadays.

In a recent publication, researchers from French and Spanish Institutions used the combination of two synchrotron light characterization techniques to study Chinese blue-and-white Ming porcelains. These characteristic porcelains, whose production flourished around the 14th century, are decorated under the glaze with Cobalt-based blue pigments that provided their distinctive blue decorations and produced during a one-step firing at high temperatures.

They were able to identify the firing temperature by determining the porcelain’s pigments and the reduction-oxidation media conditions during their production. The approach they used can also be applied on a broad range of modern and archaeological ceramics to elucidate their production technology.

Read more on the ALBA website

Image: Porcelain Jar with cobalt blue under a transparent glaze (Jingdezhen ware). Mid-15th century

Credit: Metropolitan Museum of Art.

Catalytic role of oxygen-containing groups on carbon electrodes

Catalytic role of oxygen-containing groups on carbon electrodes

The electrochemical reduction of oxygen plays a significant role in many critical applications such as gas sensors, hydrogen peroxide electrosynthesis, and electrochemical energy storage. Oxygen reduction reaction (ORR) drives the operation of fuel cells and metal-air batteries. The latter potentially can provide the highest specific energy among energy storage devices.

To increase the ORR efficiency, a catalyst immobilized on (or mixed with) conductive support is introduced to the positive electrode composition. Usually, porous sp2-carbon materials, like graphene, serve as such supporting materials. Its electronic configuration (sp2) provides the sufficient electric conductivity to the positive electrode. Nevertheless, ORR proceeds too slowly on the neat surface of ideal sp2-carbon in the absence of a catalyst.

The role of graphene imperfections (vacancies, impurity atoms, and functional groups) on catalyzing ORR (mainly in aqueous media) has been under intense investigation during the last decades. However, little is known about the effect of oxygen functionalization of carbon onORR in aprotic media (lacking the acidic protons). The interest in this process, especially in the presence of metal ions in the electrolyte, is relevant for various aprotic metal-oxygen batteries (lithium, sodium, magnesium, etc.) which are now considered as the most promising electrochemical power sources due to their outstanding theoretical performance. For such devices carbon electrodes are highly attractive due to their light weight and low cost, and the effect of carbon surface chemistry on the processes occurring upon battery operation is of great importance.

The present research shows for the first time that oxygenation of carbon electrode surface does not affect the rate of one-electron oxygen reduction in aprotic media. At the same time, in Li+-containing electrolytes, oxygen groups enhance both the rate of electrochemical Li2O2 formation and carbon electrode degradation due to faster oxidation by lithium superoxide (LiO2) intermediate yielding carbonate species as a product.

The research is led by scientists from Lomonosov Moscow State University and the Semenov Institute of Chemical Physics, in collaboration with Friedrich–Alexander–Universität Erlangen-Nürnberg, IFW Dresden, Saint Petersburg State University, Donostia International Physics Center and Massachusetts Institute of Technology. 

Read more on the ALBA website

Image: C 1s core level spectra of a) pristine and b) oxidized graphene electrodes before and after discharge. C) Model spectroelectrochemical Li-O2 cell. D) Evolution of C 1s components’ ratios upon discharge for pristine and oxidized graphene.

Cadmium contamination in rice crops

Cadmium contamination in rice crops

Cadmium is a harmful element due to its toxicity and long half-life time in human bodies. It is an extremely toxic industrial and environmental pollutant classified as a human carcinogen. Cereals are indeed the major sources of cadmium for humans and, in particular, rice, a staple food in several Asian countries, is a particularly high source of this heavy metal.

To reduce cadmium concentrations in rice, the mechanisms that determine its availability from soil to plants, its plant uptake and its transport processes need to be well understood. The present study, resulting from a scientific collaboration involving young researchers among international institutions and large scale facilities between France, Switzerland, Italy, Spain and Japan (the University of Grenoble Alpes, the ETH Zurich institute, the Okayama University, the Ente italiano Nazionale Risi and the ALBA and Soleil synchrotrons), aims to enlighten these mechanisms.

Cadmium usually binds to sulfur, getting immobilized, and the bindings with sulfur is the major driving force for cadmium isotope fractionation (when the isotopic composition of an element of a given compound changes by the transition of that compound from one physical state or chemical composition to another).

The results of this research show how soil flooding in the rice crops not only changed the cadmium speciation in the solid soils but also in soil-aqueous solutions, while vacuolar transport includes the dissociation of heavy cadmium isotopes from a sulfur donor atoms prior to membrane transport and storage in the vacuole. All these findings allow a better tracing of contaminant elements in the complex soil-plant system and permit to asset about final product toxicity when those plants are source of human food.

Read more on the ALBA website

Image: rice crops

New material with reversible pressure-induced cooling effect properties

New material with reversible pressure-induced cooling effect properties

The study of materials with giant caloric effect (reversible thermal changes induced by an external stimulus), is currently a hot topic in Materials Science since they are the best-placed candidates to develop new efficient and environmentally friendly refrigerators that must replace current devices, which feature low efficiency and use hazardous fluids.

Extensive research has shown that the caloric effects in solid-state materials can be triggered by various external stimuli: magnetic field (magnetocaloric effect), electric field (electrocaloric effect), uniaxial stress (elastocaloric effect), hydrostatic pressure (barocaloric effect) or a combination of different stresses.

While magnetocaloric and electrocaloric effects require magnetically or electrically polarized materials, barocaloric effects can be found in any compressible material, which make them more interesting.

There is therefore a need to find out caloric materials exhibiting both large isothermal entropy and adiabatic temperature changes, for which these changes are reproducible upon cyclic application and removal of hydrostatic pressure.

A research, recently published in Advanced Materials, studies the barocaloric properties of Fe3(bntrz)6(tcnset)6, a molecular material that contains a metal complex that undergoes an abrupt spin-state switching (spin-crossover transition) close to room temperature. The work was carried out by a team from the Universitat de Barcelona (Spain), the Universitat Politècnica de Catalunya (Spain), the Florida State University (USA), the University of Science and Technology Beijing (China) and the Ankara University (Turkey), in collaboration with the ALBA Synchrotron.

Read more on the ALBA website