11 July 2018
Media Releases Research Using Synchrotron Light Large Research Facilities Materials Research Matter and Material
The electronics industry expects a novel high-performance transistor made of gallium nitride to offer considerable advantages over present-day high-frequency transistors. Yet many fundamental properties of the material remain unknown. Now, for the first time, researchers at the Paul Scherrer Institute PSI have observed electrons while they were flowing in this promising transistor. For that they used one of the world's best sources of soft X-rays at PSI's Swiss Light Source SLS.
20 June 2018
SwissFEL Storage Large Research Facilities
Data storage devices based on novel materials are expected to make it possible to record information in a smaller space, at higher speed, and with greater energy efficiency than ever before. Movies shot with the X-ray laser show what happens inside potential new storage media, as well as how the processes by which the material switches between two states can be optimised.
20 June 2018
In March 2018, the nine-week MOOC “Introduction to synchrotrons and x-ray free-electron lasers” (abbreviated to “SYNCHROTRONx”) came online via the edX provider of the École Polytechnique Fédérale de Lausanne (EPFL), created by Phil Willmott of the Swiss Light Source, Paul Scherrer Institute. “MOOC” is an acronym for “massive open online course”, a teaching platform started in the first decade of this century, which has become increasingly popular in the last five to six years. MOOCs have no limits to participation and are free. Some of the most popular MOOCs can attract many tens of thousands of participants. Even the most specialized subjects may have an initial enrollment of over a thousand, more than an order of magnitude larger than that typically found in traditional higher education. There were over 70 million MOOC enrollments covering nearly 10’000 subjects offered by the top five providers in 2017 alone!
30 May 2018
A peculiar magnetic “dead layer” is detected at the surface of thin films of DyTiO3, a ferrimagnetic Mott insulator. Depth dependent X-ray absorption measurements performed at the X-Treme beamline in the Swiss Light Source indicate that this layer is associated with a deviation of the Ti valence from 3+ toward 4+ at the film surface, suppressing the magnetic coupling between Ti ions and unleashing a strong paramagnetic response from uncoupled Dy ions.
16 May 2018
The writing and deletion of magnetic Skyrmions is a fundamental step towards the fabrication of memory devices based on this promising spin configuration. Researchers at the Korea Institute of Technology have demonstrated the writing and deleting of isolated magnetic Skyrmions at room temperature in ferrimagnetic multilayer superlattice stacks using electrical currents.
6 April 2018
X-ray Free Electron Lasers (XFELs) combine the properties of synchrotron radiation (short wavelengths) and laser radiation (high lateral coherence, ultrashort pulse durations). These outstanding machines allow to study ultra-fast phenomena at an atomic level with unprecedented temporal resolution for answering the most intriguing open questions in biology, chemistry and physics.
19 March 2018
In the week of March 18-23 PSI welcomes 20 PhD students and postdocs taking part in
the HERCULES 2018 school on Neutron and Synchrotron Radiation. They will attend
lectures and perform two days of practical courses at several beam lines of the Swiss
31 January 2018
Using the FEMTO slicing source at SLS, we have studied the structural response during the photoinduced transition in a charge-ordered Pr1-x
thin films. By investigating the dynamics of both superlattice reflections and regular Bragg peaks, we disentangle the different structural contributions and analyze their relevant time-scales. Comparing these results with studies of the charge order and magnetic dynamics, a comprehensive picture of the phase transition linked to a single critical fluence fc
17 October 2017
Current-induced spin-orbit torques hold a great potential for manipulation of magnetization at ultrafast timescales. Researchers at ETH Zürich have demonstrated, using time-resolved STXM imaging at the Swiss Light Source, the influence of spin-orbit torques on the switching behaviour of Pt/Co/AlOx
11 October 2017
Highly crystalline thin films of organic semiconductors offer great potential for high-performance, low-cost flexible electronics. Researchers at IMEC Belgium have developed a new double-step thin film fabrication process that offers higher performance devices. Soft X-ray spectro-microscopy at the Swiss Light Source was used to prove that the increased performance comes from larger areas of material sharing the same molecular orientation.
26 September 2017
Media Releases Energy and Environment Research Using Synchrotron Light Environment
PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields.
1 September 2017
The SPS 2017 Prize in Condensed Matter Physics, sponsored by IBM, has been awarded to Dr. Nan Xu for his excellent work on topological quantum states. Dr. Nan Xu is a joint postdoc of Paul Scherrer Institute (PSI) and the École Polytechnique Fédérale de Lausanne (EPFL).
31 August 2017
On August 31st, 2017, SwissFEL reached the next milestone by sending the first X-rays into the Optics Hutch. The Aramis undulators of SwissFEL produced SASE-radiation with 1.2 nm wavelength. The beam entered the Aramis-beamline along the pink beam path of Bernina via two vertical offset mirrors and was detected on the diagnostic photon screen at the end of the Optics Hutch. A stable and well shaped beam with a diameter of 1.5 mm was observed. With the bendable offset mirrors we were able to manipulate the profile to enlarge and reduce the vertical its size from 660 µm (rms) down to 260 µm (rms) without introducing distortions. The gas based intensity and position monitor in the frontend could be calibrated and determined a pulse energy of approximately 5 µJ. We are now looking forward to the next commissioning time in October to commission the monochromatic beam path of Bernina and the second branchline Alvra.
18 August 2017
PSI scientists have developed a new type of X-ray optics that allows for analyzing the emission in resonant inelastic x-ray scattering (RIXS) experiments. The new approach combines the energy dispersion with imaging capabilities. In a collaborative effort with research groups from Göttingen and Hamburg, two new classes of RIXS experiments, energy mapping and RIXS imaging, have been demonstrated.
9 August 2017
Single-shot Monitoring of Ultrafast Processes via X-ray Streaking at a Free Electron Laser
The advent of x-ray free electron lasers has extended the unique capabilities of resonant x-ray spectroscopy techniques to ultrafast time scales. Here, in collaboration between researchers from PSI, Sorbonne Universités, HASYLAB/DESY, Synchrotron SOLEIL, CNRS, and Uppsala University, we report on a novel experimental method that allows retrieving with a single x-ray pulse the time evolution of an ultrafast process, not only at a few discrete time delays, but continuously over an extended time window.
24 July 2017
Controlled motions of atoms using ultrashort electric field pulses allow to manipulated the properties of a material on ultrafast timescales. Here we show how metallic structures can be used to enhance a THz electric field pulse and track the induced atomic motions with ultrashort x-ray pulses emitted by a X-ray free electron laser.
15 June 2017
We employ time-resolved resonant x-ray diffraction to study the insulator-to-metal transition that is launched via resonant excitation of an infrared-active optical phonon mode in a half doped manganite. We find that the charge order reduces promptly with a highly nonlinear (quartic) dependence on excitation fluence.
24 May 2017
Metal nanostructures can be fabricated by irradiation of suitable metal organic precursor molecules with a focused X-ray beam. This novel techniques offer the advantage of energy-selective deposition by switching of the incident photon energy due to the non-linear photon absorption cross-section of the precursor molecules for resonant excitation.
22 May 2017
For decades, the mechanism of Mott phase in Ca2
has puzzled researchers. This material is a paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling. Progress has been impeded by the lack of knowledge about the low-energy electronic structure. With our recent contribution, we provided-- using angle-resolved photoemission electron spectroscopy -- the band structure of the paramagnetic insulating phase of Ca2
21 March 2017
Turning the semimetal graphene into a technologically useful semiconductor is challenging. One way of opening a band gap is to cut graphene into nanometre-wide ribbons, but even atomic-level roughness at the ribbon edges can seriously degrade the mobility of charge carriers. Recent advances in on-surface chemistry have made it possible to obtain graphene nanoribbons with atomically precise edges through direct synthesis from molecular building blocks. Here, we report the synthesis, full structural and electronic characterization of 9-atom wide graphene nanoribbons with significantly improved electronic properties.
5 January 2017
Media Releases Energy and Environment Research Using Synchrotron Light Micro- and Nanotechnology
Eighty percent of all products of the chemical industry are manufactured with catalytic processes. Catalysis is also indispensable in energy conversion and treatment of exhaust gases. Industry is always testing new substances and arrangements that could lead to new and better catalytic processes. Researchers of the Paul Scherrer Institute PSI in Villigen and ETH Zurich have now developed a method for improving the precision of such experiments, which may speed up the search for optimal solutions.
9 November 2016
Single holmium atoms adsorbed on few monolayers of magnesium oxide are extraordinarily stable magnets. They retain a significant fraction of their magnetization when the external magnetic field is switched off. This has been shown recently in a study combining x-ray magnetic circular dichroism performed at the Swiss Light Source (SLS) and at the European Synchrotron Radiation Facility (ESRF) as well as scanning tunneling microscopy. The results open perspectives of storing and processing information at ultrahigh density.
11 October 2016
Media Releases Matter and Material Materials Research Research Using Synchrotron Light
The material neodymium nickel oxide is either a metal or an insulator, depending on its temperature. The possibility to control this transition electrically makes the material a potential candidate for transistors in modern electronic devices. By means of a sophisticated development of X-ray scattering, researchers at the Paul Scherrer Institute PSI have now been able to track down the cause of this transition: electrons around the oxygen atoms are rearranging.
20 October 2016
The first example of an insulating phase which is close to the superconducting phase in an iron-pnictide system has been recently observed in heavy Cu-doped NaFe1-x
CuxAs (x > 0.3). A combined study by angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations revealed that on-site Coulomb repulsion and enhanced Hund’s rule coupling are responsible for the insulating behavior. The results show that the insulating phase in NaFe0.5
As resembles the situation in the parent compounds of the high-Tc
19 July 2016
The use of spin-wave signals in future information processing devices can substantially reduce power consumption over present charge current based technologies. As part of an international research venture, scientists at PSI now introduced a concept to generate spin waves with nanoscale wavelengths exploiting the driven dynamics of magnetic vortex cores in magnetic heterostructures.
19 July 2016
Researchers from PSI and EPFL have demonstrated that the magnetization hysteresis and remanence of TbPc2
single-molecule magnets drastically depends on the substrate on which they are deposited. If a few atomic layers thick magnesium oxide film grown on a silver substrate is used, a record wide hysteresis and record large remanence can be obtained. Single-molecule magnets are attractive for molecular spintronics applications such as information processing or storage.
14 July 2016
Researchers have overcome a number of challenges in order to employ an advanced probe in the study of an unusual material, barium bismuth oxide (BaBiO3) – an insulating parent compound of a family of high-temperature superconductors known since the late 80s. In order to finally realize the experiments, the researchers grew and studied thin films of the material completely in situ under ultrahigh vacuum conditions. The results show that superconductivity in bismuth oxides emerges out of a novel insulating phase, where hole pairs located on combinations of the oxygen orbitals are coupled with distortions of the crystal lattice.
23 June 2016
Resonant magnetic scattering performed at the x-ray free electron laser facility LCLS (USA) has been used to investigate the magnetization dynamics of elemental Holmium. It is found that the demagnetization of conduction electrons and localized 4f magnetic moments have the same temporal evolution showing a strong coupling between the different magnetic moments.
11 April 2016
The Angle Resolved Photoemission Spectroscopy (ARPES) measurements performed on 2DEL at STO surface revealed that, at low carrier density, electrons are always accompanied by a quantized dynamic lattice deformation. Together with the electron, these phonon-cloud formed a new composite quasiparticle called Fröhlich polaron.
27. January 2016
Media Releases Matter and Material Research Using Synchrotron Light
Computers and other electronic devices account for a substantial portion of worldwide energy use. With today’s technologies, it is not possible to reduce this energy consumption significantly any further; chips in the energy-saving electronics of the future will hence have to be made from novel materials. Researchers at the Paul Scherrer Institute PSI have now found important clues in the search for such materials.