TY  - JOUR
A1  - Schick, Daniel
A1  - Bojahr, Andre
A1  - Herzog, Marc
A1  - Gaal, P.
A1  - Vrejoiu, I.
A1  - Bargheer, Matias
T1  - Following Strain-Induced Mosaicity Changes of Ferroelectric Thin Films by Ultrafast Reciprocal Space Mapping
JF  - Physical review letters
N2  - We investigate coherent phonon propagation in a thin film of ferroelectric PbZr0.2Ti0.8O3 (PZT) by ultrafast x-ray diffraction experiments, which are analyzed as time-resolved reciprocal space mapping in order to observe the in-and out-of-plane structural dynamics, simultaneously. The mosaic structure of the PZT leads to a coupling of the excited out-of-plane expansion to in-plane lattice dynamics on a picosecond time scale, which is not observed for out-of-plane compression.
Y1  - 2013
U6  - https://doi.org/10.1103/PhysRevLett.110.095502
SN  - 0031-9007
SN  - 1079-7114
VL  - 110
IS  - 9
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Shayduk, Roman
A1  - Herzog, Marc
A1  - Bojahr, Andre
A1  - Schick, Daniel
A1  - Gaal, Peter
A1  - Leitenberger, Wolfram
A1  - Navirian, Hengameh
A1  - Sander, Mathias
A1  - Goldshteyn, Jevgenij
A1  - Vrejoiu, Ionela
A1  - Bargheer, Matias
T1  - Direct time-domain sampling of subterahertz coherent acoustic phonon spectra in SrTiO3 using ultrafast x-ray diffraction
JF  - Physical review : B, Condensed matter and materials physics
N2  - We synthesize sub-THz longitudinal quasimonochromatic acoustic phonons in a SrTiO3 single crystal using a SrRuO3/SrTiO3 superlattice as an optical-acoustic transducer. The generated acoustic phonon spectrum is determined using ultrafast x-ray diffraction. The analysis of the generated phonon spectrum in the time domain reveals a k-vector dependent phonon lifetime. It is observed that even at sub-THz frequencies the phonon lifetime agrees with the 1/omega(2) power law known from Akhiezer's model for hyper sound attenuation. The observed shift of the synthesized spectrum to the higher q is discussed in the framework of nonlinear effects appearing due to the high amplitude of the synthesized phonons.
Y1  - 2013
U6  - https://doi.org/10.1103/PhysRevB.87.184301
SN  - 1098-0121
VL  - 87
IS  - 18
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Bojahr, Andre
A1  - Herzog, Marc
A1  - Mitzscherling, Steffen
A1  - Maerten, Lena
A1  - Schick, Daniel
A1  - Goldshteyn, J.
A1  - Leitenberger, Wolfram
A1  - Shayduk, R.
A1  - Gaal, P.
A1  - Bargheer, Matias
T1  - Brillouin scattering of visible and hard X-ray photons from optically synthesized phonon wavepackets
JF  - Optics express : the international electronic journal of optics
N2  - We monitor how destructive interference of undesired phonon frequency components shapes a quasi-monochromatic hypersound wavepacket spectrum during its local real-time preparation by a nanometric transducer and follow the subsequent decay by nonlinear coupling. We prove each frequency component of an optical supercontinuum probe to be sensitive to one particular phonon wavevector in bulk material and cross-check this by ultrafast x-ray diffraction experiments with direct access to the lattice dynamics. Establishing reliable experimental techniques with direct access to the transient spectrum of the excitation is crucial for the interpretation in strongly nonlinear regimes, such as soliton formation.
Y1  - 2013
U6  - https://doi.org/10.1364/OE.21.021188
SN  - 1094-4087
VL  - 21
IS  - 18
SP  - 21188
EP  - 21197
PB  - Optical Society of America
CY  - Washington
ER  - 
TY  - JOUR
A1  - Schick, Daniel
A1  - Shayduk, Roman
A1  - Bojahr, Andre
A1  - Herzog, Marc
A1  - von Korff Schmising, Clemens
A1  - Gaal, Peter
A1  - Bargheer, Matias
T1  - Ultrafast reciprocal-space mapping with a convergent beam
JF  - JOURNAL OF APPLIED CRYSTALLOGRAPHY
N2  - A diffractometer setup is presented, based on a laser-driven plasma X-ray source for reciprocal-space mapping with femtosecond temporal resolution. In order to map out the reciprocal space, an X-ray optic with a convergent beam is used with an X-ray area detector to detect symmetrically and asymmetrically diffracted X-ray photons simultaneously. The setup is particularly suited for measuring thin films or imperfect bulk samples with broad rocking curves. For quasi-perfect crystalline samples with insignificant in-plane Bragg peak broadening, the measured reciprocal-space maps can be corrected for the known resolution function of the diffractometer in order to achieve high-resolution rocking curves with improved data quality. In this case, the resolution of the diffractometer is not limited by the convergence of the incoming X-ray beam but is solely determined by its energy bandwidth.
Y1  - 2013
U6  - https://doi.org/10.1107/S0021889813020013
SN  - 0021-8898
VL  - 46
IS  - 10
SP  - 1372
EP  - 1377
PB  - WILEY-BLACKWELL
CY  - HOBOKEN
ER  -