Tag: magnetism

Iron under the ARPES Lens: how spin and magnetism shape the metal’s surface state

Iron under the ARPES Lens: how spin and magnetism shape the metal’s surface state

Researchers from the Jerzy Haber Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences in Kraków have carried out advanced experiments using angle-resolved photoemission spectroscopy (ARPES). They discovered a new surface state of iron Fe(001), whose symmetry changes depending on the magnetization direction of the layer. The results of their study have been published in the prestigious New Journal of Physics.

The electronic band structure of iron has been investigated for decades, but earlier studies were limited by experimental constraints. Today, with access to high-resolution ARPES facilities, such as the Phelix beamline at the Solaris synchrotron in Kraków, scientists can explore the electronic states of materials with unprecedented precision.

For the first time, the existence of a surface state on Fe(001) was unambiguously demonstrated in the epitaxial Fe/Au(001) system. Moreover, the Kraków team was the first to map this state across the full range of energy and momentum. Previous experiments, for example on Fe(001)/W(001), had been restricted to only a few high-symmetry directions or normal emission. By examining the surface state throughout the Brillouin zone, the researchers identified specific regions where spin–orbit coupling modifies the surface electronic states depending on the magnetization direction.

Read more on the SOLARIS website

Image: Surface state of Fe(001)/Au(001) within entire Brillouin zone and Rashba effect at the zone boudary

The Long Read: All in a spin

The Long Read: All in a spin

As 2025 marks the International Year of Quantum Technology, the ESRF contributes to the global exploration of quantum phenomena by delving into the mysteries of novel quantum magnets. These materials offer a fascinating window into the fundamental interactions of matter, yet their behaviour remains highly mysterious. To unravel them, ESRF users have had to push the boundaries of an X-ray technique. This article was first published in the March 2025 issue of the ESRFnews magazine, dedicated to quantum technology.

It is one of the most famous experiments in physics. Light illuminates a pair of slits in a wall, generating an array of bright and dark patches on a screen. The British physicist Thomas Young first performed the experiment at the turn of the 19th century to demonstrate that light can interfere with itself, behaving as a wave. Much later, quantum versions of the experiment would demonstrate something far more mysterious: that photons, electrons and other particles can exhibit wave-like interference patterns, but apparently only when no-one is watching. The experiment “has in it the heart of quantum mechanics”, wrote the American physicist and Nobel laureate Richard Feynman. “In reality, it contains the only mystery.”

Today, few scientists doubt the merits of quantum mechanics. It has proved itself through mind-boggling predictive power, not to mention a host of practical applications: semiconductor electronics, lasers, superconducting magnets, quantum cryptography and quantum computing, to name but a few. Yet it is still a subject ripe with puzzles, both in its basic interpretation and in its role in condensed matter, where each material can serve as a quantum playground.

One puzzle is the existence of peculiar types of magnetism, as studied by ESRF users such as Markus Grüninger from the University of Cologne in Germany. Unravelling these phenomena has led Grüninger and his colleagues to shift the boundaries of an X-ray technique – amazingly, in such a way as to recall Young’s famous experiment once again. “Our experiments rely on the excellent beam quality at the ESRF, the outstanding performance of the set-up at beamline ID20, and the fruitful collaboration with the beamline staff,” says Grüninger.

The technique in question is resonant inelastic X-ray scattering (RIXS). This begins with an X-ray photon knocking a tightly bound electron up to a higher atomic energy level. Almost instantaneously an electron from another high energy level relaxes into the resultant hole, releasing a new photon. By measuring the difference in energy between the incoming and outgoing photons, users can learn how the process has changed the solid in collective excitations of electron charge and spin – the latter being the basis of magnetism. The ESRF has helped develop RIXS since the 1990s, and currently offers it at two dedicated, world-leading beamlines: ID32 with soft X-rays, and ID20 with hard X-rays.

Hard X-ray photons can transfer a lot of momentum to a sample. In 2019, an international team led by Grüninger wanted to push ID20’s capabilities, and record an even greater range of momentum transfer than usual. Drawing on theory by Jeroen van den Brink at IFW Dresden in Germany, and making use of new ID20 instrumentation developed by beamline scientists Giulio Monaco (now at the University of Padova in Italy) and Marco Moretti (now at the Polytechnic University of Milan, also in Italy), the team studied the effect of large changes in momentum transfer on the intensity of the outgoing X-rays. Their sample was a crystal of an iridium oxide containing pairs or “dimers” of iridium ions. To their delight, the researchers found an interference pattern, demonstrating that the X-ray photons were exciting electrons at both iridium sites in the dimers at once – similar to light passing through Young’s double-slit, although in this case putting the dimer in an excited state

The experiment marked the beginning of RIXS interferometry, a technique that was predicted as far back as the mid 1990s. By demonstrating that the electrons in the iridium dimers experience a quantum, wave-like delocalization over a quasi-molecular dimer orbital, RIXS interferometry opened the door to the study of materials with novel magnetic properties, which physicists have been trying to understand for decades.

The most familiar type of magnetism – the sort that exists in a common fridge magnet – is ferromagnetism. In metals such as iron, it results from conduction electrons that are delocalized over an entire crystal, with spins able to align parallel to one another, producing a net magnetic moment. This is very different to one type of material with novel magnetism, the Mott insulator. Conduction in this type of material is forbidden due to strong electron repulsion, but it still has magnetism because its spins, while localized on individual ions, can interact with each other. Even more intriguing is the cluster Mott insulator, an emerging new class of material that exhibits what could be called a “local delocalization”. Here, electrons are fully delocalized over a dimer (or another small collection of ions), but they cannot propagate from one dimer to another. This results in local magnetic moments, residing not on individual ions but on quasi-molecular clusters. “In contrast to the usual electron spin, these cluster moments are something that we can tailor, by choosing the ionic species, cluster geometry, electron count, pressure and so on,” says Grüninger.

In 2022, Grüninger and colleagues used their new RIXS interferometry to unambiguously identify a cluster Mott insulator for the first time. The ID20 data could directly reveal the presence of three electron spins delocalized over an iridium dimer, creating a cluster magnetic moment [2] in a compound that is a candidate for a quantum spin liquid. The data also paved the way for a systematic exploration of more complex compounds, for example with trimers [3] or tetramers, rather than dimers. “Our results show that the trimers reside in an unexpected parameter regime that promises non-trivial magnetic moments,” says Grüninger. “They challenge previous views on trimer physics, highlighting the strength of RIXS interferometry.”

Cluster Mott insulators are exciting because of their potential as microscopic, fine-tuned magnets, as well as for their still-unexplored quantum properties. They also have potential to realize quantum “spin liquids”. First predicted by the US physicist and Nobel laureate Philip Anderson back in the 1970s, though experimentally elusive, spin liquids excel by the quantum-driven absence of magnetic order – even at temperatures close to absolute zero – that defines more conventional magnets. They are characterized by a quantum-entangled network of strongly fluctuating spins, driven by competing interactions that cannot be satisfied simultaneously. A simplified example of the situation is three spins on the vertices of a triangle: they may all want to align antiparallel to each other, but this is possible only for a pair of them, not all three simultaneously.   

Read more on ESRF website

Altermagnetism proves its place on the magnetic family tree

Altermagnetism proves its place on the magnetic family tree

There is now a new addition to the magnetic family: thanks to experiments at the Swiss Light Source SLS, researchers have proved the existence of altermagnetism. The experimental discovery of this new branch of magnetism is reported in Nature and signifies new fundamental physics, with major implications for spintronics.

Magnetism is a lot more than just things that stick to the fridge. This understanding came with the discovery of antiferromagnets nearly a century ago. Since then, the family of magnetic materials has been divided into two fundamental phases: the ferromagnetic branch known for several millennia and the antiferromagnetic branch. The experimental proof of a third branch of magnetism, termed altermagnetism, was made at the Swiss Light Source SLS, by an international collaboration led by the Czech Academy of Sciences together with Paul Scherrer Institute PSI.

The fundamental magnetic phases are defined by the specific spontaneous arrangements of magnetic moments – or electron spins – and of atoms that carry the moments in crystals. Ferromagnets are the type of magnets that stick to the fridge: here spins point in the same direction, giving macroscopic magnetism. In antiferromagnetic materials, spins point in alternating directions, with the result that the materials possess no macroscopic net magnetisation – and thus don’t stick to the fridge. Although other types of magnetism, such as diamagnetism and paramagnetism have been categorised, these describe specific responses to externally applied magnetic fields rather than spontaneous magnetic orderings in materials.

Altermagnets have a special combination of the arrangement of spins and crystal symmetries. The spins alternate, as in antiferromagnets, resulting in no net magnetisation. Yet, rather than simply cancelling out, the symmetries give an electronic band structure with strong spin polarization that flips in direction as you pass through the material’s energy bands – hence the name altermagnets. This results in highly useful properties more resemblant of ferromagnets, as well as some completely new properties.

A new and useful sibling

This third magnetic sibling offers distinct advantages for the developing field of next-generation magnetic memory technology, known as spintronics. Whereas electronics makes use only of the charge of the electrons, spintronics also exploits the spin-state of electrons to carry information.

Although spintronics has for some years promised to revolutionise IT, it’s still in its infancy. Typically, ferromagnets have been used for such devices, as they offer certain highly desirable strong spin-dependent physical phenomena. Yet the macroscopic net magnetisation that is useful in so many other applications poses practical limitations on the scalability of these devices as it causes crosstalk between bits – the information carrying elements in data storage.

More recently, antiferromagnets have been investigated for spintronics, as they benefit from having no net magnetisation and thus offer ultra-scalability and energy efficiency. However, the strong spin-dependent effects that are so useful in ferromagnets are lacking, again hindering their practical applicability.

Here enter altermagnets with the best of both: zero net magnetisation together with the coveted strong spin-dependent phenomena typically found in ferromagnets – merits that were regarded as principally incompatible.

“That’s the magic about altermagnets,” says Tomáš Jungwirth from the Institute of Physics of the Czech Academy of Sciences, principal investigator of the study. “Something that people believed was impossible until recent theoretical predictions is in fact possible.”

Read more on PSI website

Image: Juraj Krempasky, scientist at PSI and first author of the Nature publication. The experimental proof of altermagnetism was made at the SIS (COPHEE endstation) and ADRESS beamlines of the SLS.

Credit: Paul Scherrer Institut / Mahir Dzambegovic

The secret life of an electromagnon

The secret life of an electromagnon

Scientists have revealed how lattice vibrations and spins talk to each other in a hybrid excitation known as an electromagnon. To achieve this, they used a unique combination of experiments at the X-ray free electron laser SwissFEL. Understanding this fundamental process at the atomic level opens the door to ultrafast control of magnetism with light.

Within the atomic lattice of a solid, particles and their various properties cooperate in wave like motions known as collective excitations. When atoms in a lattice jiggle together, the collective excitation is known as a phonon. Similarly, when the atomic spins – the magnetisation of the atoms – move together, it’s known as a magnon.

The situation gets more complex. Some of these collective excitations talk to each other in so-called hybrid excitations. One such hybrid excitation is an electromagnon. Electromagnons get their name because of the ability to excite the atomic spins using the electric field of light, in contrast to conventional magnons: an exciting prospect for numerous technical applications. Yet their secret life at an atomic level is not well understood.

It’s been suspected that during an electromagnon the atoms in the lattice wiggle and the spins wobble in an excitation that is essentially a combination of a phonon and a magnon. Yet since they were first proposed in 2006, only the spin motion has ever been measured. How the atoms within the lattice move – if they move at all – has remained a mystery. So too has an understanding of how the two components talk to each other.

Now, in a sophisticated series of experiments at the Swiss X-ray free-electron laser SwissFEL, researchers at PSI have added these missing pieces to the jigsaw. “With a better understanding of how these hybrid excitations work, we can now start to look into opportunities to manipulate magnetism on an ultrafast timescale,” explains Urs Staub, head of the Microscopy and Magnetism Group at PSI, who led the study.

First the atoms, then the spins

In their experiments at SwissFEL, the researchers used a terahertz laser pulse to induce an electromagnon in a crystal of multiferroic hexaferrite. Using time-resolved X-ray diffraction experiments they then took ultrafast snapshots of how the atoms and spins moved in response to the excitation. With this, they proved both that the atoms within the lattice really do move in an electromagnon and also revealed how energy is transferred between lattice and spin.

A striking outcome of their study was that the atoms move first, with the spins moving fractionally later. When the terahertz pulse strikes the crystal, the electric field pushes the atoms into motion, initiating the phononic part of the electromagnon. This motion creates an effective magnetic field that subsequently moves the spins.

“Our experiments revealed that the excitation does not move the spins directly. It was previously unclear whether this would be the case,” explains Hiroki Ueda, beamline scientist at SwissFEL and the first author of the publication.

Going further, the team could also quantify how much energy the phononic component acquires from the terahertz pulse and how much energy the magnonic component acquires through the lattice. “This is an important piece of information for future applications in which one seeks to drive the magnetic system,” adds Ueda.

Read more on PSI website

Image: Hiroki Ueda, first author of the paper, working at the new Furka experimental at SwissFEL Here, using soft X-rays, Ueda and colleagues could reveal the motion of the spins during an electromagnon, complementing hard X-ray measurements of lattice vibrations made at the Bernina experimental station.

Credit: Paul Scherrer Institute/Markus Fischer

World changing science with precious photons

World changing science with precious photons

he 3.4 km long European XFEL generates extremely intense X-ray flashes used by researchers from all over the world. The flashes are produced in underground tunnels and they enable scientists to conduct a wide range of experiments including mapping atomic details of viruses, filming chemical reactions, and studying processes in the interior of planets.

Michael Schneider is a physicist at the Max Born Institute in Berlin. He uses synchrotrons and free electron lasers, such as the European XFEL, to study magnetism and magnetic materials. Michael’s fascinating #LightSourceSelfie takes you inside the European XFEL where he recalls the fact that it was large scale facilities themselves that first attracted him to his area of fundamental research. The work is bringing us closer to a new generation of computing devices that work more like the neurons in our brains that the transistors that we currently have in our computers. Michael captures the dedication of his colleagues and the facility teams, along with the type of work that you can get involved with at large scale facilities. He also gives a brilliant overview of the stages involved in conducting research at a light source. Michael is clearly very passionate about his science, but also finds time for some great hobbies too!

Ultrafast magnetism: heating magnets, freezing time

Ultrafast magnetism: heating magnets, freezing time

Magnetic solids can be demagnetized quickly with a short laser pulse, and there are already so-called HAMR (Heat Assisted Magnetic Recording) memories on the market that function according to this principle. However, the microscopic mechanisms of ultrafast demagnetization remain unclear. Now, a team at HZB has developed a new method at BESSY II to quantify one of these mechanisms and applied it to the rare-earth element Gadolinium, whose magnetic properties are caused by electrons on both the 4f and the 5d shells. This study is completing a series of experiments done by the team on Nickel, Iron-Nickel Alloys. Understanding these mechanisms is useful for developing ultrafast data storage devices.

New materials should make information processing more efficient, for example, through ultrafast spintronic devices that store data with less energy input. But to date, the microscopic mechanisms of ultrafast demagnetization are not fully understood. Typically, the process of demagnetization is studied by sending an ultrashort laser pulse to the sample, thereby heating it up, and then analyzing how the system evolves in the first picoseconds afterward.

Read more on the HZB website.

Image: The picture shows the glowing filament which keeps the sample at constant temperatures during the measurements.

Credit: © HZB

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

Dynamic, yet inertial – and definitely futuristic

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

Accoustic spin waves: towards a new paradigm of on-chip communication

Accoustic spin waves: towards a new paradigm of on-chip communication

For the first time researchers have observed directly sound-driven spin waves (magnetoacoustic waves) and have revealed its nature.

Results show that these magnetization waves can go up to longer distances (up to centimeters) and have larger amplitudes than the commonly known spin waves. The study, published in Phys. Rev. Lett., is carried out by researchers from the University of Barcelona (UB), the Institute of Materials Science of Barcelona (ICMAB-CSIC), and the ALBA Synchrotron, in collaboration with the Paul-Drude-Institut in Berlin.

Researchers have observed directly and for the first time magnetoacoustic waves (sound-driven spin waves), which are considered as potential information carriers for novel computation schemes. These waves have been generated and observed on hybrid magnetic/piezoelectric devices. The experiments were designed by a collaboration between the University of Barcelona (UB), the Institute of Materials Science of Barcelona (ICMAB-CSIC) and the ALBA Synchrotron. The results show that magnetoacoustic waves can travel over long distances -up to centimeters- and have larger amplitudes than expected.

>Read more on the ALBA website

Image: TOP: A propagating and a standing magnetization wave in ferromagnetic Nickel, driven by magnetoelastic coupling to a surface acoustic wave in a piezoelectric LiNbO3substrate. The images combine line profiles (color indicating the local magnetization direction) at different delay times between the probing X-ray pulse and the electrical SAW excitation.
BOTTOM: Scheme of the strain caused by the surface acoustic waves (SAWs) in the piezoelectric (in green color scale) and magnetic modulation in the ferromagnetic material (in orange-cyan color scale).

Dynamic pattern of skyrmions observed

Dynamic pattern of skyrmions observed

Tiny magnetic vortices known as skyrmions form in certain magnetic materials, such as Cu2OSeO3.

These skyrmions can be controlled by low-level electrical currents – which could facilitate more energy-efficient data processing. Now a team has succeeded in developing a new technique at the VEKMAG station of BESSY II for precisely measuring these vortices and observing their three different predicted characteristic oscillation modes (Eigen modes).

Cu2OSeO3 is a material with unusual magnetic properties. Magnetic spin vortices known as skyrmions are formed within a certain temperature range when in the presence of a small external magnetic field. Currently, moderately low temperatures of around 60 Kelvin (-213 degrees Celsius) are required to stabilise their phase, but it appears possible to shift this temperature range to room temperature. The exciting thing about skyrmions is that they can be set in motion and controlled very easily, thus offering new opportunities to reduce the energy required for data processing.

>Read more on the BESSY II at HZB website

Image: The illustration demonstrates skyrmions in one of their Eigen modes (clockwise).
Credit: Yotta Kippe/HZB

New material with magnetic shape memory

New material with magnetic shape memory

Researchers at the Paul Scherrer Institute PSI and ETH Zurich have developed a new material whose shape memory is activated by magnetism.

It retains a given shape when it is put into a magnetic field. It is a composite material consisting of two components. What is special about the new material is that, unlike previous shape-memory materials, it consists of a polymer and droplets of a so-called magnetorheological fluid embedded in it. Areas of application for this new type of composite material include medicine, aerospace, electronics and robotics. The researchers are now publishing their results in the scientific journal Advanced Materials.
It looks like a magic trick: A magnet moves away from a black, twisted band and the band relaxes –without any further effect (see video). What looks like magic can be explained by magnetism. The black ribbon consists of a composite of two components: a silicone-based polymer and small droplets of water and glycerine in which tiny particles of carbonyl iron float. The latter provide the magnetic properties of the material and its shape memory. If the composite material is forced into a certain shape with tweezers and then exposed to a magnetic field, this shape is retained even when the tweezers are removed. Only when the magnetic field is also removed does the material return to its original shape.

>Read more on the Swiss Light Source website

Image: Paolo Testa, first author of the study, with a model of the overall structure of the shape-memory material
Credit: Paul Scherrer Institute/Mahir Dzambegovic

Coherent scattering imaging of skyrmions

Coherent scattering imaging of skyrmions

Profiting from the coherence of synchrotron light, scientists have performed both reciprocal and real-space observations of magnetic skyrmion lattice deformation in a chiral magnet Co8Zn8Mn4.

The study of these materials is key for developing futures spintronic applications such as racetrack memory and logic devices.
The interplay between exchange interaction, antisymmetric Dzyaloshinskii-Moriya interaction, and magnetocrystalline anisotropy may cause incommensurate spin phases such as helical, conical, and Bloch-type skyrmion lattice states. The typical size of a magnetic skyrmion varies in a range from a few to a few hundred nanometers which makes them promising candidates for future spintronic applications such as skyrmion racetrack memory – with storage density higher than solid-state memory devices- and logic devices.
Coherent soft X-ray scattering and imaging are powerful tools to study the spin ordering in multicomponent magnetic compounds with element selectivity.
In this experiment, a skyrmion-hosting compound Co8Zn8Mn4 was investigated at cryogenic temperatures and applied high magnetic fields by a group of researchers from the Japanese RIKEN Center of Emergent Matter Science, National Institute for Materials Science, the Science and Technology Agency, University of Tokyo, the Institute of Materials Structure Science and Photon Factory, as well as from the ALBA Synchrotron.
 

Image: Coherent soft x-ray speckle patterns measured for Co8Zn8Mn4 sample at L3 absorption edge of Co at different temperatures 150 K, 120 K, 25 K (top panel, left to right) and applied field of 70 mT. White scale bar corresponds to 0.05 nm−1. Bottom panel shows micromagnetic simulations of the corresponding skyrmionic spin textures.

 

A compass pointing West

A compass pointing West

Researchers at the Paul Scherrer Institute PSI and ETH Zurich have discovered a special phenomenon of magnetism in the nano range.

It enables magnets to be assembled in unusual configurations. This could be used to build computer memories and switches to increase the performance of microprocessors. The results of the work have now been published in the journal Science.
Magnets are characterized by the fact that they have a North pole and a South pole. If two common magnets are held close to each other, opposite poles attract and like poles repel each other. This is why magnetic needles, such as those found in a compass, align themselves in the Earth’s magnetic field so that we can use them to determine the cardinal directions North and South and, derived from this, East and West. In the world that we experience every day with our senses, this rule is correct. However, if you leave the macroscopic world and dive into depths of much smaller dimensions, this changes. Researchers at the Paul Scherrer Institute PSI and the ETH Zurich have now discovered a very special magnetic interaction at the level of nanoscopic structures made of magnetic layers only a few atoms thick.

>Read more on the Swiss Light Source at PSI website

Image: Zhaochu Luo, lead author of the study, in front of a so-called sputter deposition tool. In the apparatus the layers of platinum, cobalt and aluminium oxide are produced. Each layer is only a few nanometers thick. Credit: Paul Scherrer Institute/Mahir Dzambegovic

How to catch a magnetic monopole in the act

How to catch a magnetic monopole in the act

Berkeley Lab-led study could lead to smaller memory devices, microelectronics, and spintronics

A research team led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has created a nanoscale “playground” on a chip that simulates the formation of exotic magnetic particles called monopoles. The study – published recently in Science Advances – could unlock the secrets to ever-smaller, more powerful memory devices, microelectronics, and next-generation hard drives that employ the power of magnetic spin to store data.

Follow the ‘ice rules’
For years, other researchers have been trying to create a real-world model of a magnetic monopole – a theoretical magnetic, subatomic particle that has a single north or south pole. These elusive particles can be simulated and observed by manufacturing artificial spin ice materials – large arrays of nanomagnets that have structures analogous to water ice – wherein the arrangement of atoms isn’t perfectly symmetrical, leading to residual north or south poles.

>Read more on the Advanced Light Source at Berkeley Lab website

Image: Full image here. This  nanoscale “playground” on a chip uses nanomagnets to simulate the formation of exotic magnetic particles called “monopoles.” Credit: Farhan/Berkeley Lab

Superferromagnetism with electric-field induced strain

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

First commissioning results for insertion devices published

First commissioning results for insertion devices published

The intense X-ray light for each of the MAX IV beamlines is generated when fast electrons fly through an array of magnets, placed in a so-called insertion device.

In a recent report, our insertion device team present the commissioning results for the first nine of these beamline specific instruments.
At synchrotrons like MAX IV, we accelerate electrons to velocities close to the speed of light. The electrons are injected into storage rings where they travel turn after turn inside a vacuum tube, guided by the strong forces of hundreds of carefully tuned magnets. At certain places along the electron path, the magnets are arranged in arrays called insertion devices that make the electrons wiggle from side to side as they fly through. When the electrons perform this motion, they emit energy in the form of intense X-rays. Each beamline needs its dedicated insertion device, built to produce X-rays optimised for the measurement techniques performed there.
The insertion device team have now published the first commissioning results. At the time the report was written, twelve insertion devices were installed, and nine successfully commissioned to deliver according to specifications. Six of them have been built in-house, and two are transferred from the old MAX-lab and refurbished. The remaining insertion devices come from Hitachi and our French synchrotron colleague SOLEIL.

>Read more on the MAX IV Laboratory website