No. I/13 - 28 March 2013
PSI photon, neutron and muon user facilities newsletter
important milestones for the realization of the new SwissFEL facility were reached in 2012. In September the Swiss Parliament approved the federal program for education and research for the 2013-16 period, which includes the mandate for PSI to build SwissFEL. On the 14th of December 2012 the budget for federal building construction was approved including the funding for the SwissFEL building. The legally valid building permit for SwissFEL arrived at the end of January 2013. The preparation of the site in the
Würenlingen Waldis almost finished. The connections of the site to the PSI infrastructures are still ongoing.
A consortium of three Swiss companies named
EquiFEL Suissewas awarded the exclusive contract as full service general contractor for the construction of the SwissFEL Building and its technical infrastructure. Signing of the contract took place on the 7th of February 2013. First works for the building and its technical infrastructure will start in April 2013. End of 2014 the finished building will be delivered to the Paul Scherrer Institute. The installation of the accelerator and the experimental stations will follow in 2015 and 2016. The first beam is foreseen for the end of 2016. Pilot experiments should start in spring 2017.
In order to prepare for SwissFEL and to start work in the exciting area of ultra-fast spectroscopy and nanocrystallography, several teams from Swiss universities and PSI are using the few existing facilities worldwide to do first experiments, among others: group of S. Johnson (ETHZ) and P. Beaud / U. Staub (PSI), group of G. Schertler (PSI/ETHZ) and B. Pedrini (PSI), group of J. van Bokhoven (PSI/ETHZ), J. Dousse (U Fribourg), and B. Patterson (PSI), group of C. David (PSI).
Rafael Abela, on behalf of the SwissFEL team, PSI
SLS - Life Science & Material Science: Imaging fluctuations with X-ray microscopy
Microscopy using X-rays offers unique three-dimensional insights for the life and material sciencesP. Thibault et al, Nature 494, 68 (2013)
A schematic of the setup employed for the experimental demonstration. X rays are focused and scatter off a test sample that can be displaced laterally with nanometer precision. The diffraction pattern produced by the scattered X rays is collected by a detector. The sample is reconstructed on a computer from the diffraction data (see other images). X-rays allow an inside look at structures that cannot be imaged using visible light. They are used to investigate nanoscale structures of objects as varied as single cells or magnetic storage media. Yet, high-resolution images impose extreme constraints on both the X ray microscope and the samples under investigation. Researchers at the Technische Universität München, Germany, and the Paul Scherrer Institut in Villigen, Switzerland, now showed how to relax these conditions without loss of image quality. They further showed how to image objects featuring fast fluctuations, such as the rapid switching events that determine the life time of data storage in magnetic materials. They demonstrated their method with an experiment at the Swiss synchrotron SLS and with computer simulations. The results have been published in the science journal Nature.
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SINQ - Magnetism: Useful frustration
Persistent Spin Dynamics Intrinsic to Amplitude-Modulated Long-Range Magnetic OrderM. Pregelj et al, Physical Review Letters 109, 227202 (2012)
An incommensurate elliptical helical magnetic structure in the frustrated coupled-spin-chain system FeTe2O5Br is surprisingly found to persist down to 53(3) mK (T/TN ≈ 1/200), according to neutron scattering and muon spin relaxation. In this state, finite spin fluctuations at T → 0 are evidenced by muon depolarization, which is in agreement with specific-heat data indicating the presence of both gapless and gapped excitations. We thus show that the amplitude-modulated magnetic order intrinsically accommodates contradictory persistent spin dynamics and long-range order and can serve as a model structure to investigate their coexistence.
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SμS - Material Science: Tailoring of electronic and magnetic properties
New diluted ferromagnetic semiconductor with Curie temperature up to 180 K and isostructural to the 122 iron-based superconductorsK. Zhao et al, Nature Communications 4, 1442 (2013)
Diluted magnetic semiconductors have received much attention due to their potential applications for spintronics devices. A prototypical system (Ga,Mn)As has been widely studied since the 1990s. The simultaneous spin and charge doping via hetero-valent (Ga3+,Mn2+) substitution, however, resulted in severely limited solubility without availability of bulk specimens. Here we report the synthesis of a new diluted magnetic semi- conductor (Ba1-xKx)(Zn1-yMny)2As2, which is isostructural to the 122 iron-based superconductors with the tetragonal ThCr2Si2 (122) structure. Holes are doped via (Ba2+,K1+) replacements, while spins via isovalent (Zn2+,Mn2+) substitutions. Bulk samples with x = 0.1-0.3 and y = 0.05-0.15 exhibit ferromagnetic order with TC up to 180 K, which is comparable to the highest TC for (Ga,Mn)As and significantly enhanced from TC up to 50 K of the 111-based Li(Zn,Mn)As. Moreover, ferromagnetic (Ba,K)(Zn,Mn)2As2 shares the same 122 crystal structure with semiconducting BaZn2As2, antiferromagnetic BaMn2As2 and superconducting (Ba,K)Fe2As2, which makes them promising for the development of multilayer functional devices.
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Foundation stone ceremony of the SwissFEL building
The groundbreaking ceremony of the SwissFEL building will be organized at PSI on July 3rd 2013, with participation of representatives from the scientific community, political authorities, of the local community as well as from academic groups.
CRISP 2nd annual meeting at PSI
From 18 to 21 of March 2013 the CRISP annual meeting was held at PSI. The meeting was a great success. The talks given by experts from different facilities gave an inspiring view of progress made within the different collaboration topics of the CRISP project. More than 100 participants from the different CRISP partner facilities participated at the meeting. We are grateful for the excellent contributions which were made.
New calls for proposalsSLS: PX-beamlines
deadline: June 15, 2013
SLS: non-PX beamlines
deadline: September 15, 2013
deadline: May 15, 2013
deadline: June 2013
An overview about all proposal submission deadlines of the PSI facilities can be obtained here.
Upcoming eventsMaMaSELF status meeting 2013
May 21-24, 2013, Rigi Kulm, Switzerland
ESS symposium: neutrons for future energy strategy
May 27-29, 2013, PSI Villigen, Switzerland
The Zurich School of Crystallography 2013
June 9-22, 2013, Zurich, Switzerland
Gordon research conference on Electron Distribution and Chemical Bonding
July 2-7, 2013, Les Diablerets, Switzerland
ICNS 2013: International Conference on Neutron Scattering
July 7-11, 2013, Edinburgh, UK
12th PSI Summer School on Condensed Matter Physics
August 17-25, 2013, Zuoz, Switzerland
3rd Joint User Meeting at PSI: JUM@P 2013
September 18-20, 2013, PSI Villigen, Switzerland
Facility newsSLS: Combining Scanning Probe and X-Ray Microscopy for Nanoanalytics, NanoXAS
SLS-NanoXAS is a novel x-ray microscope combining x-ray spectroscopy with scanning probe microscopy. While the first one gives access to chemical information, the second reveal the sample topology or other physical properties accessible by SPM. The instrument uses Fresnel zone plates to focus x-rays (down to 40nm spot @ 270 1800 eV) onto a semi-transparent sample which is raster scanned through the beam. A scanning probe microscope (SPM) is looking on the down stream side of the sample. In complement to the material contrast arising from the x-ray transmission chemical sensitivity, topology, magnetic forces, elasticity, friction, conductivity may be successively assessed using the SPM. Furthermore scanning transmission x-ray microscopy (STXM) images have been recorded using the AFM tip to measure the transmitted x-rays allowing the record of the topological image in parallel (N. Pilet, et al., Nanotechnology 23 (47), 475708 (2012)).
SINQ: New SAC chairman
Prof. Peter Böni from the Technical University of Munich has been appointed as new chairman of the SINQ Scientific Advisory Committee from summer 2013. He will follow Prof. Andrew Boothroyd from the University of Oxford, who acted as chairman of the SINQ SAC since 2006. The Paul Scherrer Institut, the PSI NUM department and the whole SINQ team thank Andrew for his outstanding contributions and the highly efficient and fruitful collaboration over the last years.
SμS: New LEM spectrometer based on G-APDs
A new low energy muon spectrometer for the use of external field directions parallel to the sample surface has recently been taken into operation. It is based on Geiger-mode Avalanche Photodiodes (G-APD) coupled to plastic scintillators which allows a much more compact design than with the traditionally used photomultipliers leaving space for more complex sample environments. In addition, the new detector system is segmented in the forward/backward direction allowing more flexible measuring conditions.