Scientific Highlights

20 December 2019
Illustration of the crystal structure of (MA)PbBr3

Ultrafast diffuse x-ray scattering of a hybrid perovskite crystal

Organic–inorganic ‘hybrid’ perovskites have recently gained attention as a low-cost alternative to silicon solar cells. However, many properties of these materials are still poorly understood. In particular, how imperfections in the crystals, which can be both static or dynamic, affect energy transport remains unclear.

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18 September 2018

Bernina status first summer shutdown

The summer shutdown was used to install more missing hardware. With the new components the Bernina instrument will be already very close to the full design capabilities when the exciting time of user experiments will begin in 2019.

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5 September 2018
Figure 1 (a) Transient relative x-ray intensity of the (1.5 0.5 0.5) superlattice reflection of Sr0.97Ca0.03TiO3 upon above bandgap excitation with 40 fs pulses Inset: STO crystal structure as seen along the c-axis. phi measures the antiferrodistortive rotation of the oxygen octahedra (exaggerated) and represents the order parameter. (b) Calculated energy change per STO cubic unit cell as a function of oxygen displacement u/u0 along the in-plane cubic crystal axes resulting from the octahedral rotation at …

Moving Atoms by Photodoping

Understanding how and how fast we can drive atoms to create a structural phase transition is of fundamental interest as it directly relates to many processes in nature. Here we show that a photoexcitation can drive a purely structural phase transition before the energy is relaxed in the material that corresponds to a “warmer” equilibrated state.

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20 June 2018
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Movie directors with extra roles

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.

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6 April 2018

A first glance at the SwissFEL x-rays wave-front

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.

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31 January 2018
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Photoinduced transitions in magnetoresistive manganites: A comprehensive view

Using the FEMTO slicing source at SLS, we have studied the structural response during the photoinduced transition in a charge-ordered Pr1-xCaxMnO3 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 is proposed.

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30 November 2017
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First time resolved Pilot Experiment by SwissFEL: Semiconductor to metal transition in Ti3O5 nanocrystals

On the 30th of November 2017 SwissFEL saw its first time resolved pilot experiment in the Bernina experimental station of the SwissFEL ARAMIS beamline. A team of scientists from the University of Rennes, ESRF and PSI, led by Marco Cammarata (Univ. Rennes) and Henrik Lemke (PSI), successfully started the experimental phase at SwissFEL. The goal was to study the picosecond dynamics of a light-induced phase transition from a semiconductor to metallic crystal structure in a Titanium Oxide (D).

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29 November 2017

Coupling between a Charge Density Wave and Magnetism in an Heusler Material

The prototypical magnetic memory shape alloy Ni2MnGa undergoes various phase transitions as a function of the temperature, pressure, and doping. In the low-temperature phases below 260 K, an incommensurate structural modulation occurs along the [110] direction which is thought to arise from the softening of a phonon mode. It is not at present clear how this phenomenon is related, if at all, to the magnetic memory effect. Here we report time-resolved measurements which track both the structural and magnetic components of the phase transition from the modulated cubic phase as it is brought into the high-symmetry phase.

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