- Following the first successful demonstration of EUV pump / EUV probe transient grating measurements at FERMI to which our group contributed , two new important new results have been obtained and published [2,3].
- In collaboration with colleagues from Siegen and Stockholm as well as the local team at FERMI, we made the first observation of transient nanoscale gratings of magnetization, see Fig. 1 below .
- We have done the first EUV pump / EUV probe experiment in the reflection geometry and measured 50 GHz surface acoustic waves in SrTiO3 .
- Reflection mode measurements greatly expand the range of possible samples (otherwise samples must be in the form of ultrathin membranes in order to be able to transmit the EUV probe).
- In collaboration with collaegues from Paul Scherrer Institut and others, we have made the first transient grating experiment with hard x-ray excitation at SwissFEL .
Figure. 1 Transient gratings of magnetization. (a) The concept of the experiment. The sample is kept in a homogeneous magnetization state by the external field H, which is larger than the coercive field. The two EUV pump pulses generate a nanoscale spatial modulation of the temperature, producing a transient magnetization grating in the sample. The dynamics of the magnetization grating are monitored via transient diffraction (dashed arrows) of a timedelayed probe pulse, tuned to a magnetic absorption edge. After each FEL shot, the sample is returned to the initial magnetic state by the field H. (b) Images of the transient diffraction signal collected with a CCD camera at different pump−probe delays are indicated in the individual panels. (c) EUV TG signal from a 9 nm-thick film of CoGd alloy as a function of the time delay between the pump and probe pulses recorded with and without an external magnetic field. The period of the magnetization grating is 44 nm.