TY  - JOUR
A1  - Woerner, Michael
A1  - von Korff Schmising, Clemens
A1  - Bargheer, Matias
A1  - Zhavoronkov, Nickolai
A1  - Vrejoiu, Ionela
A1  - Hesse, Dietrich
A1  - Alexe, Marin
A1  - Elsaesser, Thomas
T1  - Ultrafast structural dynamics of perovskite superlattices
N2  - Femtosecond x-ray diffraction provides direct insight into the ultrafast reversible lattice dynamics of materials with a perovskite structure. Superlattice (SL) structures consisting of a sequence of nanometer-thick layer pairs allow for optically inducing a tailored stress profile that drives the lattice motions and for limiting the influence of strain propagation on the observed dynamics. We demonstrate this concept in a series of diffraction experiments with femtosecond time resolution, giving detailed information on the ultrafast lattice dynamics of ferroelectric and ferromagnetic superlattices. Anharmonically coupled lattice motions in a SrRuO3/PbZr0.2Ti0.8O3 (SRO/ PZT) SL lead to a switch-off of the electric polarizations on a time scale of the order of 1 ps. Ultrafast magnetostriction of photoexcited SRO layers is demonstrated in a SRO/SrTiO3 (STO) SL.
Y1  - 2009
UR  - http://www.springerlink.com/content/100501
U6  - https://doi.org/10.1007/s00339-009-5174-6
SN  - 0947-8396
ER  - 
TY  - JOUR
A1  - Zamponi, Flavio
A1  - Ansari, Zunaira
A1  - von Korff Schmising, Clemens
A1  - Rothhardt, Philip
A1  - Zhavoronkov, Nickolai
A1  - Woerner, Michael
A1  - Elsaesser, Thomas
A1  - Bargheer, Matias
A1  - Trobitzsch-Ryll, Timo
A1  - Haschke, Michael
T1  - Femtosecond hard X-ray plasma sources with a kilohertz repetition rate
N2  - Laser-driven plasma sources of femtosecond hard X-ray pulses have found widespread application in ultrafast X- ray diffraction. The recent development of plasma sources working at kilohertz repetition rates has allowed for diffraction experiments with strongly improved sensitivity, now revealing subtle fully reversible changes of the geometry of crystal lattices. We provide a brief review of this development and present a novel plasma source with an optimized mechanical and optical design, providing a high flux of several 10(10) photons/s at the Cu-K alpha energy of 8.04 keV and a pulse duration of a parts per thousand currency sign300 fs. First experiments, including the generation of Debye-Scherrer diffraction patterns from Si powder, demonstrate the high performance of this source.
Y1  - 2009
UR  - http://www.springerlink.com/content/100501
U6  - https://doi.org/10.1007/s00339-009-5171-9
SN  - 0947-8396
ER  -