PSI summer school 2014
The PSI summer school 2014 on Condensed Matter Research will be organized at the Institut Montana in Zug, Switzerland from August 9-15, 2014. The topic of the school will be 'Exploring time, energy and length scales in condensed matter' and the school will be followed by hands-on practical training at the PSI large user facilities SINQ, SμS and SLS. Online registration and detailed information is available from the school's webpage.
Unique insight into carbon fibers on the nanoscale
Novel carbon materials are promising candidates for light and robust low-cost materials of the future. Understanding their mechanical properties benefits from highly resolved three-dimensional (3D) maps of their porosity and density fluctuations in uninterrupted representative volumes, but these are difficult to obtain with conventional imaging methods.
Frustration-induced nanometre-scale inhomogeneity in a triangular antiferromagnet
Phase inhomogeneity of otherwise chemically homogenous electronic systems is an essential ingredient leading to fascinating functional properties, such as high-Tc superconductivity in cuprates, colossal magnetoresistance in manganites and giant electrostriction in relaxors. In these materials distinct phases compete and can coexist owing to intertwined ordered parameters. Charge degrees of freedom play a fundamental role, although phase-separated ground states have been envisioned theoretically also for pure spin systems with geometrical frustration that serves as a source of phase competition.
High-tech right up to the roof
The construction work in the woods is well underway: the building for SwissFEL, the Paul Scherrer Institute’s new large research facility, is due for completion by the end of 2014. The demands on the building are high: It needs to ensure that the sensitive equipment can run smoothly.
X-ray tomography reaches 16 nm isotropic 3D resolution
Tomographic microscopy has become an invaluable imaging method in both life and materials sciences. Oftentimes, high resolving power is required simultaneously with the ability to characterize large, statistically representative sample volumes. To this task, researchers at the Paul Scherrer Institut have established ptychographic computed tomography.
Spintronics: deciphering a material for future electronics
Topological insulators are the key to future spintronics technologies. EPFL scientists have unraveled how these strange materials work, overcoming one of the biggest obstacles on the way to next-generation applications.Read the full story
Aerosol measurements: PSI researchers help to close regional gaps around the globe
Aerosols are small particles in the atmosphere. They can influence the global climate by way of direct absorption or scattering of solar radiation, or by acting as nuclei for cloud formation. Efforts by scientists to exactly quantify these effects and then improve climate models are impeded by the lack of a global network of aerosol measurement stations. To remedy this situation, researchers at the Paul Scherrer Institute to facilitate continuous aerosol measurements at sites where the paucity of data is the greatest.
How rock pores in deep repositories close over
Chemical reactions will change the nature of the deep repository and the surrounding rock (clay rock); that much is certain. But to what extent and with what impact on safety? Researchers from the Paul Scherrer Institute are looking to answer this question with the aid of a combination of experiments and computer simulations.
Switching of magnetic domains reveals spatially inhomogeneous superconductivity
The interplay of magnetic and charge fluctuations can lead to quantum phases with exceptional electronic properties. A case in point is magnetically-driven superconductivity, where magnetic correlations fundamentally affect the underlying symmetry and generate new physical properties. The superconducting wavefunction in most known magnetic superconductors does not break translational symmetry.
Magnetoelastic Excitations in the Pyrochlore Spin Liquid Tb2Ti2O7
Tb2Ti2O7 is often referred to as a spin liquid as it does indeed remain in a magnetically disordered phase with spin dynamics down to 0.05 K, but this itself is a surprise since there are strong expectations of magnetic order and/or a structural distortion. However, throughout the spin liquid regime there are also strong signs of magnetoelastic coupling, leading to the suggestion that both spin and structural degrees of freedom are frustrated.
Supervolcano eruptions driven by melt buoyancy in large silicic magma chambers
Super-eruptions that dwarf all historical volcanic episodes in erupted volume and environmental impact are abundant in the geological record. Such eruptions of silica-rich magmas form large calderas. The mechanisms that trigger these supereruptions are elusive because the processes occurring in conventional volcanic systems cannot simply be scaled up to the much larger magma chambers beneath super volcanoes.
Reaction Conditions of Methane-to-Methanol Conversion Affect the Structure of Active Copper Sites
Determining the structure of the active Cu sites, which are associated with the methane conversion intermediate during stepwise, low-temperature, methane-to-methanol conversion, represents an important step for the upgrade of this reaction route to a viable process. Quick X-ray absorption spectroscopy allowed us to follow the electronic and structural changes to the active Cu sites during reaction with methane and during desorption of the activated intermediate. A large fraction (41%) of the oxygen-activated CuII reacted with methane and underwent reduction to CuI.
Bulk superconductivity in undoped T'-La1.9Y0.1CuO4 probed by muon spin rotation
The Meissner effect has been directly demonstrated by depth-resolved muon spin rotation measurements in high-quality thin films of the T'-structured cup rate, T'-La1.9Y0.1CuO4, to confirm bulk superconductivity (Tc ≈ 21 K) in its undoped state. The gradual expelling of an external magnetic field is observed over a depth range of ∼ 100 nm in films with a thickness of 275(15) nm, from which the penetration depth is deduced to be 466(22) nm. Based on this result, we argue that the true ground state of the “parent” compound of the n-type cuprates is not a Mott insulator but a strongly correlated metal with colossal sensitivity to apical oxygen impurities.
Superconductivity switched on by magnetic field
Superconductivity and magnetic fields are normally seen as rivals à very strong magnetic fields normally destroy the superconducting state. Physicists at the Paul Scherrer Institute have now demonstrated that a novel superconducting state is only created in the material CeCoIn5 when there are strong external magnetic fields. This state can then be manipulated by modifying the field direction. The material is already superconducting in weaker fields, too. In strong fields, however, an additional second superconducting state is created which means that there are two different superconducting states at the same time in the same material.
Experiments in the clouds – how soot influences the climate
PSI-researcher Martin Gysel receives prestigious European funding (ERC Consolidator Grant) for his studies on the role of soot in cloud formation and global warming.
Promises of cyclotron-produced 44Sc as a diagnostic match for trivalent beta - emitters: In vitro and in vivo study of a 44Sc-DOTA-folate conjugate
Research Division Biology and Chemistry (BIO), Folate Receptor Targeting Group, Head Cristina Müller. In recent years, implementation of 68Ga-radiometalated peptides for PET imaging of cancer has attracted the attention of clinicians. Herein, we propose the use of 44Sc (half-life = 3.97 h, average β+ energy [Eβ+av] = 632 keV) as a valuable alternative to 68Ga (half-life = 68 min, Eβ+av = 830 keV) for imaging and dosimetry before 177Lu-based radionuclide therapy.
The Paul Scherrer Institute runs two of the energy competence centres of the Swiss government
As part of the Energy Strategy 2050 the Swiss government and parliament have decided to increase support for energy research in Switzerland. This includes the setting up of seven interuniversity networked Swiss Competence Centres in Energy Research (SCCERs). In the SCCERs ETH Domain institutions, the universities and the universities of the applied sciences are to join forces with industrial partners to develop new competencies and solutions in the decisive action areas of the shift in energy policy. The Paul Scherrer Institute PSI will act as the leading house in two of the SCCERs à storage and biomass à that have already been given the green light. They will begin their work in 2014.
An infection tool with a metallic core
Thanks to the analysis of protein samples at the PSI, Lausanne researchers have managed to demonstrate which instrument bacteria use to transmit diseasesResearchers from ETH Lausanne EPFL have described how a particular strain of bacteria transmits diseases with unprecedented precision. The team of scientists headed by Petr Leiman, an assistant professor at the EPFL’s Laboratory of Structural Biology and Biophysics, demonstrated that the tip of a bacterial infection tool consists of a PAAR protein, which envelops a metal atom and tapers off to a sharp point. The findings are based on measurements carried out at the Swiss Light Source (SLS), one of the three large research facilities at the Paul Scherrer Institute (PSI).
Fuel cell membrane from the Paul Scherrer Institute better than its commercial counterparts
A novel polymer electrolyte membrane from the Paul Scherrer Institute PSI has demonstrated longer durability in a laboratory test than the best commercially available counterparts. The breakthrough was achieved by modifying a reasonably priced plastic film through radiation activation and subsequent attachment of functional constituents via a grafting reaction. The modified polymer is not only durable à it could also reduce the membrane production costs by 50 to 80 percent. The membrane could be used in applications such as hydrogen fuel cells or electrolysers for hydrogen production from water.
How botox binds to neurons
Botox is a highly dangerous toxin that causes paralysis. In cosmetic applications it is used to temporarily eliminate wrinkles and in medicine as a treatment for migraine or to correct strabismus. An international research team has now established how the toxin molecule binds to the neuron whose activity is then blocked by the poison. The findings may be useful for the development of improved drugs with a lower risk of overdosage.
Sharper image of a catalyst – warts and all
A catalyst made of the noble metal ruthenium supported on a carbon substrate is frequently used industrially. A prime example is the synthesis of ammonia, which, among other things, is involved in the production of nitrogenous fertilisers. Many research groups all over the world are looking to optimise this type of catalyst as it would increase the efficiency of one of the economically most important industrial processes. However, our understanding of how the catalytically active centres in the catalyst develop has been somewhat patchy thus far. Researchers from the Paul Scherrer Institute PSI can now unveil some fresh insights.
Zukünftige Computerchips mit "elektronischem Blutkreislauf"
Im Rahmen des Sinergia-Programms fördert der Schweizerische Nationalfonds das dreijährige Forschungsvorhaben REPCOOL. Unter der Leitung von IBM Research à Zürich arbeiten in diesem Projekt Wissenschaftler der ETH Zürich, des Paul Scherrer Instituts in Villigen und der Università della Svizzera italiana in Lugano gemeinsam an der Erforschung eines elektronischen Blutkreislaufs für zukünftige 3D-Computerchips. Vom menschlichen Gehirn inspiriert, entwickeln die Forscher ein Mikrokanalsystem mit einer elektrochemischen Flussbatterie, die 3D-Chipstapel gleichzeitig kühlen und mit Energie versorgen. Ultimatives Ziel ist die Entwicklung eines Supercomputers in PC-Grösse.This news release is only available in German.
Electrons with a "split personality"
Above the transition temperature, some electrons in the superconducting material La1.77Sr0.23CuO4 behave as if they were in a conventional metal, others as in an unconventional one à depending on the direction of their motion. This is the result of experiments performed at the SLS. The discovery of this anisotropy makes an important contribution towards understanding high-temperature superconductors. The effect will also have to be taken into account in future experiments and theories of high-temperature superconductors.
The SwissFEL facility: laser light from avalanche-like amplification
SwissFEL will create X-ray light with laser-like characteristics. The strong amplification of the light needed is produced by a process known as micro-bunching à electron packets break up in the undulator into thin layers which emit light in phase. At the same time, another process called seeding is being studied, in which one will be able to establish the properties of the light even more precisely.
Unique insight into carbon fibers on the nanoscale
The investigation of the mechanical properties of carbon fibers benefits from highly resolved three-dimensional density maps within representative volumes, but such images are not easily obtained with standard methods. Scientists from the Paul Scherrer Institut in collaboration with Honda R&D in Germany have recently visualized density distributions on the sub-micrometer scale within entire carbon fiber sections, revealing surprising graphite distributions within the fibers. This capability will prove useful for the systematic characterization of fibers, contributing to the development of light and robust materials at lower costs.
Magnetismus im Stress: Gleichzeitiger Anti- und Ferromagnetismus
Die gleichzeitige Existenz von Magnetismus und Ferroelektrizät in einem Material ist selten. Setzt sich dieser Magnetismus aus mehreren unabhängigen, magnetischen Grundzuständen zusammen, ist das ungewöhnlich. Einer schweizerisch-französischen Zusammenarbeit unter Leitung des Paul Scherrer Instituts ist es gelungen, mehrere magnetische Grundzustände in einem Material zu realisieren und detailliert zu untersuchen.
Rare particle decays support standard model
Researchers from the Paul Scherrer Institute have observed for the first time the extremely rare decay of the Bs meson into two muons. They have determined its decay frequency with sufficient accuracy using data collected by the CMS detector at CERN. Their result agrees with the predictions of the standard model of particle physics.
Interface superconductor with gap behaviour like a high-temperature superconductor
The physics of the superconducting state in two-dimensional (2D) electron systems is relevant to understanding the high-transition-temperature copper oxide superconductors and for the development of future superconductors based on interface electron systems. But it is not yet understood how fundamental superconducting parameters, such as the spectral density of states, change when these superconducting electron systems are depleted of charge carriers.
A promising new method for the diagnosis of breast cancer
A new mammography procedure that could generate substantial added value for the diagnosis of breast cancer in medical practice has just been published in the scientific journal Investigative Radiology. The method was developed at PSI in cooperation with the Certified Breast Centre at the Kantonsspital (cantonal hospital in) Baden and Philips as an industrial partner and is making the tiniest tissue changes visible. This has the potential to improve the early detection of breast cancer. Further studies in women suffering from breast cancer are to prove in a definitive manner the added value of the method.
Why lithium-ion-batteries fail
Materials in lithium ion battery electrodes expand and contract during charge and discharge. These volume changes drive particle fracture, which shortens battery lifetime. A group of ETH and PSI scientists have quantified this effect for the first time using high-resolution 3D movies recorded using x-ray tomography at the Swiss Light Source.