TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Bodenthin, Yves
A1  - Grenzer, Jörg
A1  - Geue, Thomas
A1  - Möhwald, Helmuth
A1  - Kurth, Dirk G.
T1  - Structure and temperature behavior of metallo-supramolecular assemblies
N2  - A detailed structural analysis of a Langmuir-Blodgett (LB) multilayer composed of a polyelectrolyte-amphiphile complex (PAC) is presented. The PAC is self-assembled from metal ions, ditopic bis-terpyridines, and amphiphiles. The vertical structure of the LB multilayer is investigated by X-ray reflectometry. The multilayer has a periodicity of 57 A, which corresponds to an architecture of flat lying metallo-supramolecular coordination polyelectrolyte (MEPE) rods and upright-standing amphiphiles (dihexadecyl phosphate, DHP). In-plane diffraction reveals hexagonal packing of the DHP molecules. Using extended X-ray absorption fine structure (EXAFS) experiments, we prove that the central metal ion is coordinated to the terpyridine moieties in a pseudo-octahedral coordination environment. The Fe-N bond distances are 1.82 and 2.0 angstrom, respectively. Temperature resolved measurements indicate a reversible phase transition in a temperature range up to 55 degrees C. EXAFS measurements indicate a lengthening of the average Fe-N bond distance from 1.91 to 1.95 angstrom. The widening of the coordination cage upon heating is expected to lower the ligand field stabilization, thus giving rise to spin transitions in these composite materials
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Bhattacharya, M. K.
A1  - Sanyal, M. K.
A1  - Geue, Thomas
T1  - Glass transition in Ultrathin Polymer Films : a Thermal Expansion Study
N2  - The glass transition process gets affected in ultrathin films having thickness comparable to the size of the molecules. We observe systematic broadening of the glass transition temperature (T-g) as the thickness of an ultrathin polymer film reduces below the radius of gyration but the change in the average T-g was found to be very small. The existence of reversible negative and positive thermal expansion below and above T-g increased the sensitivity of our thickness measurements performed using energy-dispersive x-ray reflectivity. A simple model of the T-g variation as a function of depth expected from sliding motion could explain the results
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grenzer, Jörg
A1  - Bischoff, Lothar
T1  - Grazing-incidence diffraction strain analysis of a laterally patterned Si wafer treated by focused Ge and An ion beam implantation
N2  - Strain analysis of a laterally patterned Si-wafer was carried out utilizing X-ray grazing-incidence diffraction with synchrotron radiation. The lateral patterning was done by focused ion beam implantation using an ion source of liquid AuGeSi alloy. Samples were prepared by either 35 keV Au+ ions (dose: 0.2, 2 x 10(14) cm(-2)) or 70 keV Ge++ ions (dose: 8 X 10(14) cm(-1)). It was shown that due to implantation a periodical defect structure is created consisting of both implanted and not implanted stripes. The evaluated depth distribution of defects within the implanted stripes corresponds to that obtained by TRIM calculation. The induced strain distribution, however, shows no periodicity. This can be explained by an overlap of the strain fields created in each implanted stripe. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Bodenthin, Yves
A1  - Möhwald, Helmuth
A1  - Kurth, Dirk G.
T1  - Inducing spin crossover in metallo-supramolecular polyelectrolytes through an amphiphilic phase transition
N2  - A phase transition in an amphiphilic mesophase is explored to deliberately induce mechanical strain in an assembly of tightly coupled metal ion coordination centers. Melting of the alkyl chains in the amphiphilic mesophase causes distortion of the coordination geometry around the central transition metal ion. As a result, the crystal field splitting of the d-orbital subsets decreases resulting in a spin transition from a low-spin to a high-spin state. The diamagnetic-paramagnetic transition is reversible. This concept is demonstrated in a metallo-supramolecular coordination polyelectrolyte-amphiphile complex self-assembled from ditopic bis-terpyridines, Fe(II) as central transition metal, and dialkyl phosphates as amphiphiles. The magnetic properties are studied in a Langmuir-Blodgett multilayer. The modularity of this concept provides extensive control of structure and function from molecular to macroscopic length scales and gives access to a wide range of new molecular magnetic architectures such as nanostructures, thin films, and liquid crystals
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Gorfman, S. V.
A1  - Tsirelson, Vladimir G.
A1  - Pietsch, Ullrich
T1  - X-ray diffraction by a crystal in a permanent external electric field : general considerations
N2  - The variations of X-ray diffraction intensities from a crystal in the presence of a permanent external electric field is modeled analytically using a first-order stationary perturbation theory. The change in a crystal, induced by an external electric field, is separated into two contributions. The first one is related to a pure polarization of an electron subsystem, while the second contribution can be reduced to the displacements of the rigid pseudoatoms from their equilibrium positions. It is shown that a change of the X-ray diffraction intensities mainly originates from the second contribution, while the influence of the pure polarization of a crystal electron subsystem is negligibly small. The quantities restored from an X-ray diffraction experiment in the presence of an external electric field were analyzed in detail in terms of a rigid pseudoatomic model of electron density and harmonic approximation for the atomic thermal motion. Explicit relationships are derived that link the properties of phonon spectra with E-field-induced variations of a structure factor, pseudoatomic displacements and piezoelectric strains. The displacements can be numerically estimated using a model of independent atomic motion if the Debye - Waller factors and pseudoatomic charges are known either from a previous single-crystal X-ray diffraction study or from density functional theory calculations. The above estimations can be used to develop an optimum strategy for a data collection that avoids the measurements of reflections insensitive to the electric-field-induced variations
Y1  - 2005
SN  - 0108-7673
ER  - 
TY  - JOUR
A1  - Karageorgiev, Peter
A1  - Neher, Dieter
A1  - Schulz, Burkhard
A1  - Stiller, Burkhard
A1  - Pietsch, Ullrich
A1  - Giersig, Michael
A1  - Brehmer, Ludwig
T1  - From anisotropic photo-fluidity towards nanomanipulation in the optical near-field
N2  - An increase in random molecular vibrations of a solid owing to heating above the melting point leads to a decrease in its long-range order and a loss of structural symmetry. Therefore conventional liquids are isotropic media. Here we report on a light-induced isothermal transition of a polymer film from an isotropic solid to an anisotropic liquid state in which the degree of mechanical anisotropy can be controlled by light. Whereas during irradiation by circular polarized light the film behaves as an isotropic viscoelastic fluid, it shows considerable fluidity only in the direction parallel to the light field vector under linear polarized light. The fluidization phenomenon is related to photoinduced motion of azobenzene-functionalized molecular units, which can be effectively activated only when their transition dipole moments are oriented close to the direction of the light polarization. We also describe here how the photofluidization allows nanoscopic elements of matter to be precisely manipulated
Y1  - 2005
SN  - 1476-1122
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Leitenberger, Wolfram
A1  - Vartanyants, Ivan A.
T1  - Coherence experiments using white synchrotron radiation
N2  - Experiments at the bending magnet beamline at BESSY II (EDR beamline) profit from the excellent coherence properties of third generation synchrotron sources. Considering the exponentially decaying incident spectrum, and because no optical elements are installed except slits and vacuum windows, coherence experiments can be performed between 5 keV < E < 15 keV. First, the energy dependence of spatial coherence properties were determined measuring diffraction at single and double pinholes. Next, the coherent white radiation was used to probe the morphology of thin films in reflection geometry. The recorded intensity maps (reflectivity versus sample position) provide speckle patterns which reveal the locally varying sample morphology. Setting the incident angle, alpha(i), smaller or larger than the critical angle of total external reflection, alpha(c), one should be able to separate the surface height profile from the subsurface density modulation of a sample. The validity of this approach is verified at the example of reciprocal space maps taken from a polymer surface where we could reconstruct the lateral height profile from speckle data. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Henneberg, Oliver
A1  - Rochon, Paul
A1  - Panzner, Tobias
A1  - Finkelstein, Kenneth D.
A1  - Geue, Thomas
A1  - Saphiannikova, Marina
A1  - Pietsch, Ullrich
T1  - In-situ Investigation of Surface Relief Grating Formation in Photosensitive Polymers
Y1  - 2004
UR  - http://www.chess.cornell.edu/pubs/csnm2004/research/insitu.pdf
ER  - 
TY  - JOUR
A1  - Leitenberger, Wolfram
A1  - Pietsch, Ullrich
T1  - A monolithic Fresnel bimirror for hard X-rays and its application for coherence measurements
N2  - Experiments using a simple X-ray interferometer to measure the degree of spatial coherence of hard X-rays are reported. A monolithic Fresnel bimirror is used at small incidence angles to investigate synchrotron radiation in the energy interval 5-50 keV with monochromatic and white beam. The experimental setup was equivalent to a Young's double-slit experiment for hard X-rays with slit dimensions in the micrometre range. From the high-contrast interference pattern the degree of coherence was determined.
Y1  - 2007
UR  - http://journals.iucr.org/s/issues/2007/02/00/wl5137/wl5137.pdf
U6  - https://doi.org/10.1107/S0909049507003846
SN  - 0909-0495
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Leitenberger, Wolfram
A1  - Vartanyants, Ivan A.
T1  - Coherence experiments at the EDR-beamline of BESSY II
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Talalaev, V
A1  - Tomm, JW
A1  - Elsaesser, T
A1  - Zeimer, Ute
A1  - Fricke, J
A1  - Knauer, A
A1  - Kissel, H
A1  - Weyers, Markus
A1  - Tarasov, GG
A1  - Grenzer, Jörg
A1  - Pietsch, Ullrich
T1  - Carrier dynamics in laterally strain-modulated InGaAs quantum wells
N2  - We investigate the transient recombination and transfer properties of nonequilibrium carriers in an In0.16Ga0.84As/GaAs quantum well (QW) with an additional lateral confinement implemented by a patterned stressor layer. The structure thus contains QW- and quantum-wire-like areas. At low excitation densities, photoluminescence (PL) transients from both areas are well described by a rate equation model for a three-level system with a saturable interlevel carrier transfer representing the lateral drift of carriers from the QW regions into the wires. Small-signal carrier lifetimes for QW, wires, and transfer time from QW to wire are 180, 190, and 28 ps, respectively. For high excitation densities the time constants of the observed transients increase, in agreement with the model. In addition, QW and wire PL lines merge indicating a smoothening of the potential difference, i.e., the effective carrier confinement caused by the stressor structure becomes weaker with increasing excitation. (c) 2005 American Institute of Physics
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Pfeiffer, Franz
A1  - Robinson, Ian K.
T1  - Substrate morphology repetition in "thick" polymer films
N2  - Using Grazing-incidence small-angle scattering (GISAXS) technique we investigated the surface morphology of polymer films spin-coated on different silicon substrates. As substrates we used either technologically smooth silicon wafers or the same silicon wafer coated with thin aluminium or gold films which show a granular structure at the surface. Although the polymer thickness exceeds 300 nm the GISAXS pattern of the film shows the same in-plane angle distribution Delta2theta as the underlying substrate. Annealing the polymer films at a temperature above its glass transition temperature Delta2theta changed from a broad to a narrow distribution as it is typically for films on pure silicon. The experiment can be interpreted by roughness replication and density fluctuation within the polymer film created while spin-coating at room temperature. Due to the low segment mobility there are density fluctuations which repeat the surface morphology of the substrate. Above the glass temperature the polymer density can be homogenized independently from the morphology of the substrate. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Zeimer, Ute
A1  - Pietsch, Ullrich
A1  - Grenzer, Joerg
A1  - Fricke, J.
A1  - Knauer, A.
A1  - Weyers, Markus
T1  - Optimised two layer overgrowth of a lateral strain-modulated nanostructure
N2  - Recently it has been shown that lateral carrier confinement in an InGaAs quantum well (QW) embedded in GaAs can be achieved by using a laterally patterned InGaP stressor layer on top of the heterostructure. To exploit this effect in a device the structure has to be planarized by a second epitaxial step. It has been shown that the lateral strain modulation almost vanishes after overgrowth with GaAs, whereas overgrowth with a single ternary layer of opposite strain compared to the stressor layer suffers from strain induced decomposition. Here we show that the lateral carrier confinement of the initially free standing nanostructure can almost be maintained using a two step process for overgrowth, where a strained thin ternary layer is grown first followed by GaAs up to complete planarization of the patterned structure. Thickness and composition of the ternary layer are adjusted on the basis of finite element calculations of the strain distribution (FEM). The strain field achieved after overgrowth is probed by X-ray grazing- incidence diffraction (GID). (c) 2005 Elsevier B.V. All rights reserved
Y1  - 2005
SN  - 0925-8388
ER  - 
TY  - BOOK
A1  - Pietsch, Ullrich
A1  - Holý, Václav
A1  - Baumbach, Tilo
T1  - High resolution X-ray scattering from thin films and lateral nanostructures
T3  - Advanced texts in physics : physics and astronomy online library
Y1  - 2004
SN  - 0-387-40092-3
PB  - Springer
CY  - New York
ET  - 2. ed.
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Saphiannikova, Marina
A1  - Henneberg, Oliver
A1  - Geue, Thomas
T1  - Non-linear effects during inscription of azobenzene surface relief gratings
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Saphiannikova, Marina
A1  - Henneberg, Oliver
A1  - Gene, T. M.
A1  - Pietsch, Ullrich
A1  - Rochon, Paul
T1  - Nonlinear effects during inscription of azobenzene surface relief gratings
N2  - Surface relief gratings were inscribed on azobenzene polymer films using a pulselike exposure of an Ar+ laser. The inscription process was initiated by a sequence of short pulses followed by much longer relaxation pauses. The development of the surface relief grating was probed by a He-Ne laser measuring the scattering intensity of the first- order grating peak. The growth time of the surface relief grating was found to be larger than the length of the pulses used. This unusual behavior can be considered as a nonlinear material response associated with the trans-cis isomerization of azobenzene moieties. In this study the polymer stress was assumed to be proportional to the number of cis-isomers. One-dimensional viscoelastic analysis was used to derive the polymer deformation. The rate of trans-cis isomerization increases with the intensity of the inscribing light; in the dark it is equal to the rate of thermal cis- trans isomerization. The respective relaxation times were estimated by fitting theoretical deformation curves to experimental data
Y1  - 2004
SN  - 1520-6106
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Gupta, Ajay
A1  - Gupta, Mukul
A1  - Ayachit, S.
A1  - Rajagopalan, S.
A1  - Balamurgan, A. K.
A1  - Tyagi, A. K.
T1  - Iron self-diffusion in nanocrystalline FeCr thin films
N2  - Thin films of amorphous Fe85Zr15 alloy were deposited by ion-beam sputtering of a composite target. Analogous to the melt-spun amorphous alloys of similar composition, the crystallization of the amorphous film occurs in two steps, however, with a substantially reduced thermal stability. After completion of the first crystallization step which starts at 473 K, the microstructure consists of 12 nm nanocrystals of bcc-Fe embedded in a grain boundary region of the remaining amorphous phase. At 673 K, the remaining amorphous phase transforms into the Fe2Zr alloy. The self-diffusion measurements of iron in the nanocrystalline state and in the parent amorphous state has been carried out using secondary ion mass spectroscopy (SIMS) depth profiling and neutron reflectivity techniques. In contrast to the case of finemet Fe73.5Si13.5B9Nb3Cu1 alloy, where a significant enhancement of diffusivity takes place in the nanocrystalline state, in the present case the diffusivity in the nanocrystalline state is similar to that in the parent amorphous state. It is suggested that in this system the atomic diffusion occurs mainly via the grain boundary regions. The calculated values of the pre-exponential factor and the activation energy for the diffusion are D-0 = 1 x 10(-14+/-1) m(2)/s and E = (0.7 +/- 0.1) eV respectively. (C) 2004 Published by Elsevier B.V.
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grenzer, Jörg
A1  - Grigorian, Souren A.
A1  - Weyers, Markus
A1  - Zeimer, Ute
A1  - Feranchuk, S.
A1  - Fricke, J.
A1  - Kissel, H.
A1  - Knauer, A.
A1  - Tränkle, G.
T1  - Nanoengineering of lateral strain-modulation in quantum well heterostructures
N2  - We have developed a method to design a lateral band-gap modulation in a quantum well heterostructure. The lateral strain variation is induced by patterning of a stressor layer grown on top of a single quantum well which itself is not patterned. The three-dimensional (3D) strain distribution within the lateral nanostructure is calculated using linear elasticity theory applying a finite element technique. Based on the deformation potential approach the calculated strain distribution is translated into a local variation of the band-gap energy. Using a given vertical layer structure we are able to optimize the geometrical parameters to provide a nanostructure with maximum lateral band-gap variation. Experimentally such a structure was realized by etching a surface grating into a tensile-strained InGaP stressor layer grown on top of a compressively strained InGaAs-single quantum well. The achieved 3D strain distribution and the induced band-gap variation are successfully probed by x-ray grazing incidence diffraction and low-temperature photoluminescence measurements, respectively
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Hazra, S.
A1  - Chini, T. K.
A1  - Sanyal, M. K.
A1  - Grenzer, Jörg
T1  - Ripple structure of crystalline layers in ion beam induced Si wafers
N2  - Ion-beam-induced ripple formation in Si wafers was studied by two complementary surface sensitive techniques, namely atomic force microscopy (AFM) and depth-resolved x-ray grazing incidence diffraction (GID). The formation of ripple structure at high doses (similar to7x10(17) ions/cm(2)), starting from initiation at low doses (similar to1x10(17) ions/cm(2)) of ion beam, is evident from AFM, while that in the buried crystalline region below a partially crystalline top layer is evident from GID study. Such ripple structure of crystalline layers in a large area formed in the subsurface region of Si wafers is probed through a nondestructive technique. The GID technique reveals that these periodically modulated wavelike buried crystalline features become highly regular and strongly correlated as one increases the Ar ion-beam energy from 60 to 100 keV. The vertical density profile obtained from the analysis of a Vineyard profile shows that the density in the upper top part of ripples is decreased to about 15% of the crystalline density. The partially crystalline top layer at low dose transforms to a completely amorphous layer for high doses, and the top morphology was found to be conformal with the underlying crystalline ripple
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Gupta, Amod
A1  - Paul, A.
A1  - Meneghini, C.
A1  - Mibu, K.
A1  - Maddalena, S.
A1  - Dal Toe, S.
A1  - Principi, G.
T1  - Structural characterization of epitaxial Fe/Cr multilayers using anomalous x-ray scattering and neutron reflectivity
N2  - The interface structure of epitaxial Fe/Cr multilayers was studied using anomalous X-ray and neutron reflectivity. The analysis of X-ray reflectivity at three different energies provided a reliable information about the interface roughnesses. It is found that the Cr-on-Fc interface is more diffused as compared to the Fe-on-Cr interface and that the roughness exhibits a significant increase with increasing depth. The magnetic roughness, as determined from neutron reflectivity, is lower than the geometrical roughness, in conformity with the behavior of a number of magnetic thin films and multilayers. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Henneberg, Oliver
A1  - Geue, Thomas
A1  - Pietsch, Ullrich
A1  - Winter, Bernd
T1  - Investigation of azobenzene side group orientation in polymer surface relief gratings by means of photoelectron spectroscopy
N2  - The molecular orientation of azobenzene side groups in polymer films before (nonpatterned) and after (patterned) development of a surface relief grating has been investigated by photoelectron spectroscopy using synchrotron radiation. The photoemission spectra obtained for 60-100 eV photons of a patterned and a nonpatterned surface are similar when the polarization vector of the synchrotron light is parallel to the grating vector. However, for perpendicular excitation, considerable spectral intensity differences can be observed for 9-14 eV electron binding energy. The observed changes are attributed to the formation of well-oriented azobenzenes at the surface. (C) 2004 American Institute of Physics
Y1  - 2004
UR  - http://scitation.aip.org/journals/doc/APPLAB-ft/vol_84/iss_9/1561_1.html
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Jarre, A.
A1  - Salditt, T.
A1  - Panzner, Tobias
A1  - Pfeiffer, F.
T1  - White beam x-ray waveguide optics
N2  - We report a white beam x-ray waveguide (WG) experiment. A resonant beam coupler x-ray waveguide (RBC) is used simultaneously as a broad bandpass (or multibandpass) monochromator and as a beam compressor. We show that, depending on the geometrical properties of the WG, the exiting beam consists of a defined number of wavelengths which can be shifted by changing the angle of incidence of the white x-ray synchrotron beam. The characteristic far-field pattern is recorded as a function of exit angle and energy. This x-ray optical setup may be used to enhance the intensity of coherent x-ray WG beams since the full energetic acceptance of the WG mode is transmitted. (C) 2004 American Institute of Physics
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Mukhopadhyay, M. K.
A1  - Sanyal, M. K.
A1  - Datta, A.
A1  - Mukherjee, M.
A1  - Geue, Thomas
A1  - Grenzer, Jörg
T1  - Transition from two-dimensional to three-dimensional melting in Langmuir-Blodgett films
N2  - Results of energy-dispersive x-ray reflectivity and grazing incidence diffraction studies of Langmuir-Blodgett films exhibited evolution of conventional three-dimensional melting from continuous melting, characteristic of two- dimensional systems, as a function of deposited monolayers. Continuous expansion followed by a sharp phase transition of the in-plane lattice was observed before the melting point and found to be independent of number of deposited layers. Evolution of conventional melting with an increase in the number of monolayers could be quantified by measuring stiffness against tilting of the vertical stack of molecules, which are kept together by an internal field. The internal field as defined in this model reduces as the in-plane lattice expands and the sample temperature approaches melting point. The sharpness of the melting transition, which has been approximated by a Langevin function, increases with the number of deposited monolayers
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Davaasambuu, Jav
A1  - Kochin, V.
A1  - Schwarz, K. H.
A1  - Blaha, Pawel
T1  - The atomistic origin of the inverse piezoelectric effect in a-quartz
N2  - Ab initio calculations have been carried out using the FP-APW+lo method in order to understand the atomic origin of the inverse piezoelectric effect in x-quartz. The external electric field was modelled by a saw-like potential V-ext in order to achieve translational symmetry within a supercell (SC) containing 72 atoms. The original trigonal quartz structure was repeated along the [110] direction, which corresponds to the direction of the external field. An electric field with 550 kV/mm was applied and the atomic positions of the SC were relaxed until the forces acting on the atoms vanished. In parts of the SC, V-ext changes almost linearly and thus the relaxed atomic positions can be used to determine the structural response due to the external electric field. The calculations provide the piezoelectric modulus of the correct order of magnitude. In contrast to previous models and in agreement with recent experimental results, the atomic origin of the piezoelectric effect can be described by a rotation of slightly deformed SiO4 tetrahedra against each other. The change of the Si-O bond lengths and the tetrahedral O-Si-O angles is one order of magnitude smaller than that of the Si-O-Si angles between neighbouring tetrahedra. The calculated changes of X-ray structure factors are in agreement with experiment when the theoretical data are extrapolated down to the much smaller field strength that is applied in the experiment (E < 10 kV/mm). (C) 2004 Elsevier Ltd. All rights reserved
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Davaasambuu, Jav
A1  - Pucher, Andreas
A1  - Kochin, V.
T1  - Atomistic origin of the inverse piezoelectric effect in alpha-SiO2 and alpha-GaPO4
Y1  - 2003
UR  - http://www.edpsciences.org/articles/epl/pdf/2003/12/7666.pdf?access=ok
SN  - 0295-5075
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Leitenberger, Wolfram
A1  - Wendrock, Horst
A1  - Bischoff, Lothar
A1  - Panzner, Tobias
A1  - Grenzer, Jörg
A1  - Pucher, Andreas
T1  - Double pinhole diffraction of white synchrotron radiation
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
T1  - Evidence of a density grating under light induced formation of surface relief gratings at polymers containing azobenzene moieties
Y1  - 2003
UR  - http://scitation.aip.org/getpdf/servlet/ GetPDFServlet?filetype=pdf&id=JAPIAU000094000002000963000001&idtype=cvips
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Hesse, A.
A1  - Zhuang, Y.
A1  - Holý, Vaclav
A1  - Stangl, Jochen
A1  - Zerlauth, S.
A1  - Schaffler, F.
A1  - Bauer, Günther
T1  - X-ray grazing-incidence study of inhomogeneous strain relaxation in Si/SiGe wires
Y1  - 2003
SN  - 0168-583X
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Tsirelson, Vladimir G.
A1  - Gorfan, S. V.
T1  - X-ray scattering amplitude of an atom in a permanent external electric field
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grigorian, Souren A.
A1  - Grenzer, Jörg
A1  - Vartanyants, Ivan A.
T1  - Thermal diffuse scattering in grazing incidence diffraction
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Leitenberger, Wolfram
A1  - Grenzer, Jörg
A1  - Bodenthin, Th.
A1  - Geue, Thomas
A1  - Möhwald, Helmuth
T1  - Coherence experiments at the energy-dispersive reflectometry beamline at BESSY II
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grigorian, Souren A.
A1  - Grenzer, Jörg
A1  - Feranchuk, S.
A1  - Zeimer, Ute
T1  - Grazing-incidence diffraction study of strain-modulated single quantum well nanostructures
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Bhattacharya, M. K.
A1  - Mukherjee, M.
A1  - Sanyal, M. K.
A1  - Geue, Thomas
A1  - Grenzer, Jörg
T1  - Energy dispersive x-ray reflectivity technique to study thermal properties of polymer films
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
A1  - Grenzer, Jörg
A1  - Grigorian, Souren A.
A1  - Fricke, J.
A1  - Gramlich, S.
A1  - Bugge, F.
A1  - Weyers, Markus
A1  - Trankle, G.
T1  - Influence of lateral patterning geometry on lateral carrier confinement in strain-modulated InGaAs- nanostructures
Y1  - 2003
ER  - 
TY  - JOUR
A1  - Geue, Thomas
A1  - Henneberg, Oliver
A1  - Grenzer, Jörg
A1  - Pietsch, Ullrich
A1  - Natansohn, Almeria
A1  - Rochon, Paul
A1  - Finkelstein, Kenneth D.
T1  - Formation of a buried density grating on thermal erasure of azobenzene polymer surface gratings
Y1  - 2002
SN  - 0927-7757
ER  - 
TY  - JOUR
A1  - Bodenthin, Yves
A1  - Grenzer, Jörg
A1  - Lauter, Robert
A1  - Pietsch, Ullrich
A1  - Lehmann, Pit
A1  - Kurth, Dirk G.
A1  - Möhwald, Helmuth
T1  - Temperature and time resolved x-ray scattering at thin organic films
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Geue, Thomas
A1  - Henneberg, Oliver
A1  - Pietsch, Ullrich
T1  - X-ray reflectivity from sinusoidal surface relief gratings
Y1  - 2002
SN  - 0023-4753
ER  - 
TY  - JOUR
A1  - Send, Sebastian
A1  - von Kozierowski, Marc
A1  - Panzner, Tobias
A1  - Gorfman, Semen
A1  - Nurdan, Kivanc
A1  - Walenta, Albert H.
A1  - Pietsch, Ullrich
A1  - Leitenberger, Wolfram
A1  - Hartmann, Robert
A1  - Strüder, Lothar
T1  - Energy-dispersive Laue diffraction by means of a frame-store pnCCD
Y1  - 2009
UR  - http://journals.iucr.org/j/journalhomepage.html
U6  - https://doi.org/10.1107/S0021889809039867
SN  - 0021-8898
ER  - 
TY  - JOUR
A1  - Panzner, Tobias
A1  - Gleber, Gudrun
A1  - Sant, Tushar
A1  - Leitenberger, Wolfram
A1  - Pietsch, Ullrich
T1  - Coherence experiments at the white-beam beamline of BESSYI
N2  - The third-generation X-ray source BESSYII (Berlin, Germany) provides coherent X-ray radiation which can be used for static and dynamic speckle analysis. Recently we have demonstrated that one can perform experiments with coherent white radiation provided by a bending magnet (5 < E < 20 keV). In this paper we show that the diffraction figure of the initial pinhole must be considered for the interpretation of coherent experiments. The reflectivity spectrum of a sample results from the Fresnel diffraction of the incident pinhole deformed by the static speckle features of the sample surface. For dynamical experiments all speckle like features alter with time whereas the pure Fresnel fringes remain constant. (c) 2007 Published by Elsevier B.V.
Y1  - 2007
UR  - http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TW0-4N08M4P-1- F&_cdi=5548&_user=1584062&_orig=search&_coverDate=05%2F23%2F2007&_sk=994849985&view=c&wchp=dGLbVzW- zSkWA&md5=3a09375f874dccd9b382488e9d0
U6  - https://doi.org/10.1016/j.tsf.2006.12.002
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Penacorada, Florencio
A1  - Geue, Thomas
A1  - Pietsch, Ullrich
A1  - Brehmer, Ludwig
T1  - In-plane structure of uranylarachidate multilayers
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Lichanot, Albert
A1  - Azavant, P.
A1  - Pietsch, Ullrich
T1  - Ab-initio Hartree-Fock study of the electronic charge density of the cubic boron nitride and its comparison with the experiment
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Hansen, N. K.
T1  - A critical review of the valence charge density in GaAs
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Stahn, Jochen
A1  - Möhle, Marcus
A1  - Pietsch, Ullrich
T1  - Accurate structure determination for GaAs using Pendellösung oscillation
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Brajpuriya, Ranjeet
A1  - Tripathi, Sumit
A1  - Sharma, Abhishek
A1  - Chaudhari, S.M.
A1  - Phase, D.M.
A1  - Gupta, Ajay
A1  - Shripathi, Thoudinja
A1  - Leitenberger, Wolfram
A1  - Pietsch, Ullrich
A1  - Laxmi, N.
T1  - Temperature dependent energy-dispersive X-ray diffraction and magnetic study of Fe/Al interface
N2  - In situ temperature dependent energy-dispersive structural and magnetic study of electron beam evaporated Fe/Al multilayer sample (MLS) has been investigated. The structural studies show the formation of an intermixed FeAl transition layer of a few nanometers thick at the interface during deposition, which on annealing at 300 degrees C transforms to B2FeAl intermetallic phase. Magnetization decreases with increase in temperature and drops to minimum above 300 degrees C due to increase in anti-ferromagnetic interlayer coupling and formation of nonmagnetic FeAl phase at the interface. The Curie temperature (T-c) is found to be 288 degrees C and is much less than that of bulk bcc Fe.
Y1  - 2007
UR  - http://www.sciencedirect.com/science/journal/01694332
U6  - https://doi.org/10.1016/j.apsusc.2007.04.069
SN  - 0169-4332
ER  - 
TY  - JOUR
A1  - Leitenberger, Wolfram
A1  - Hartmann, Robert
A1  - Pietsch, Ullrich
A1  - Andritschke, Robert
A1  - Starke, Ines
A1  - Strüder, Lothar
T1  - Application of a pnCCD in X-ray diffraction : a three-dimensional X-ray detector
N2  - The first application of a pnCCD detector for X-ray scattering experiments using white synchrotron radiation at BESSY II is presented. A Cd arachidate multilayer was investigated in reflection geometry within the energy range 7 keV < E < 35 keV. At fixed angle of incidence the two-dimensional diffraction pattern containing several multilayer Bragg peaks and respective diffuse-resonant Bragg sheets were observed. Since every pixel of the detector is able to determine the energy of every incoming photon with a resolution Delta E/E similar or equal to 10(-2). a three-dimensional dataset is finally obtained. In order to achieve this energy resolution the detector was operated in the so-called single-photon- counting mode. A full dataset was evaluated taking into account all photons recorded within 10(5) detector frames at a readout rate of 200 Hz. By representing the data in reciprocal-space coordinates, it becomes obvious that this experiment with the pnCCD detector provides the same information as that obtained by combining a large number of monochromatic scattering experiments using conventional area detectors.
Y1  - 2008
UR  - http://onlinelibrary.wiley.com/iucr/10.1107/S0909049508018931
U6  - https://doi.org/10.1107/S0909049508018931
ER  - 
TY  - JOUR
A1  - Siebrecht, R.
A1  - Schreyer, A.
A1  - Englisch, Uwe
A1  - Pietsch, Ullrich
A1  - Zabel, Hartmut
T1  - The new reflectometer ADAM at the ILL
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Paschke, K.
A1  - Geue, Thomas
A1  - Barberka, Thomas Andreas
A1  - Bolm, A.
A1  - Pietsch, Ullrich
A1  - Rösch, M.
A1  - Batke, Edwin
A1  - Faller, F.
A1  - Kerkel, K.
A1  - Oshiniwo, J.
A1  - Forchel, Alfred
T1  - Characterization of lateral semiconductor nano structures by means of x-ray grazing-incidence diffraction
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Herrmann, A.
A1  - Kaupp, G.
A1  - Geue, Thomas
A1  - Pietsch, Ullrich
T1  - AFM and GID investigations of the gas-solid diazotation of 4-sulfanil-acid-monohydrat single crystals
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Bolm, A.
A1  - Englisch, Uwe
A1  - Penacorada, Florencio
A1  - Gerstenberger, M.
A1  - Pietsch, Ullrich
T1  - Temperature and time dependent investigations of cd- and uranyl-stearate multilayers by means of neutron reflectivity measurements
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Rose, Dirk
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
T1  - Characterization of InGaAs single quantum wells buried in GaAs[001] by grazing incidence diffraction
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Paschke, K.
A1  - Pietsch, Ullrich
A1  - Wang, K. H.
A1  - Forchel, Alfred
A1  - Baumbach, Tilo
A1  - Zeimer, Ute
T1  - Identification of a buried single quantum well within surface structurized semiconductors using depth resolved x-ray grazing-incidence diffraction
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Englisch, Uwe
A1  - Gutberlet, T.
A1  - Seitz, R.
A1  - Oeser, R.
A1  - Pietsch, Ullrich
T1  - Thermally induced rearrangement of fatty acid salt molecules in Langmuir-Blodgett multilayers
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Knochenhauer, Gerald
A1  - Barberka, Thomas Andreas
A1  - Geue, Thomas
A1  - Pietsch, Ullrich
A1  - Brehmer, Ludwig
A1  - Hodge, P.
A1  - Tredgold, Richard H.
T1  - In-plane structure of perfluorotetra decanoic acid Langmuir-Blodgett films and films formed by vacuum deposition
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Holý, Vaclav
A1  - Strömmer, R.
A1  - Englisch, Uwe
T1  - X-ray and neutron diffuse scattering from multilayers of fatty acid salt molecules
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Dietzel, Birgit
A1  - Freydank, Anke-Christine
A1  - Geue, Thomas
A1  - Pietsch, Ullrich
A1  - Brehmer, Ludwig
T1  - Lateral structure of thermally treated oxadiazole Langmuir-Blodgett films
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Englisch, Uwe
A1  - Barberka, Thomas Andreas
A1  - Pietsch, Ullrich
A1  - Höhne, U.
T1  - Investigation of the chain-chain interface in a lead-stearate multilayer using neutron reflectivity
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Geue, Thomas
A1  - Stumpe, Joachim
A1  - Pietsch, Ullrich
A1  - Haak, M.
A1  - Kaupp, G.
T1  - Photochemically induced changes of optical anisotropy and surface of LB-multilayers built up by an amphiphilic and liquid crystalline copolymer conating azobenzene moieties
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Englisch, Uwe
A1  - Barberka, Thomas Andreas
A1  - Pietsch, Ullrich
A1  - Höhne, U.
A1  - Reiche, Jürgen
A1  - Dietzel, Birgit
T1  - Neutronenreflektivität an Langmuir-Blodgett-Strukturen
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Stömmer, Ralph
A1  - Zeimer, Ute
A1  - Pietsch, Ullrich
T1  - Diffuse Röntgenstreuung an LB-Filmen
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Mahler, Willy
A1  - Bodenstein, G.
A1  - Pietsch, Ullrich
T1  - Phasentransformationen in Cd-Stearat-Multischichten bei unterschiedlichen Metallionenkonzentrationen
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Greue, Th.
A1  - Barberka, Thomas Andreas
A1  - Pietsch, Ullrich
A1  - Stumpe, Joachim
A1  - Kauppe, G.
T1  - Zeitaufgelöste Untersuchungen an Photochromen LB-Multischichten mittels energiedispersiver Röntgenkleinwinkelstreuung, in-plane Beugung und AFM
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Englisch, Uwe
A1  - Pietsch, Ullrich
A1  - Reiche, Jürgen
A1  - Dietzel, Birgit
T1  - Neutronenreflektivität von teildeuterierten LB-Filmen mit verschiedenen Verhältnissen on protonierten zu deuterierten Schichten
Y1  - 1995
ER  - 
TY  - JOUR
A1  - Neißendorfer, Frank
A1  - Bolm, A.
A1  - Pietsch, Ullrich
T1  - Energy dispersive X-ray reflectometry and X-ray grazing incidence diffraction from organic multilayers
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Barberka, Thomas Andreas
A1  - Knochenhauer, Gerald
A1  - Woolley, Martin
A1  - Pietsch, Ullrich
T1  - Comprehensive structure investigation and computer modelling of perfluorododecanoic acid multilayers formed by in-vacuo thermal evaporation
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Barberka, Thomas Andreas
A1  - Janietz, Dietmar
A1  - Hofmann, Dieter
A1  - Pietsch, Ullrich
A1  - Brehmer, Ludwig
T1  - X-ray structure investigation and computer modelling of Langmuir-Blodgett films formed from disc-shaped pentaalkines
Y1  - 1994
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Pietsch, Ullrich
A1  - Fink, Hans-Peter
A1  - Lemmetyinen, Helge
T1  - A comparison fo x-ray methods for structure refinement of Langmuir-Blodgett multilayers
N2  - The possibilities and limits of structure refinement of Langmuir-Blodgett films by means of symmetrical reflection of X- rays are described using the example of a stearic acid multilayer. Three different techniques for the determiantion of the electron density profile from reflectivity data are compared; a Fourier method, a Patterson method, and model calculations. The important role of the a priori information for finding the besft structure model is outlined.
Y1  - 1992
ER  - 
TY  - JOUR
A1  - Reinhold, Beate
A1  - Geue, Thomas
A1  - Huber, Patrick
A1  - Sant, Tushar
A1  - Pietsch, Ullrich
A1  - Sztucki, Michael
T1  - In situ and ex situ SAXS investigation of colloidal sedimentation onto laterally patterned support
N2  - We report on in situ investigations of colloidal ordering during gravity sedimentation from a colloidal suspension onto a prepatterned support using a polymeric surface relief grating (SRG) as the support. The ordering of colloids with a diameter of 420 nm was investigated by means of grazing-incidence small-angle X-ray scattering (GISAXS) and transmission SAXS using a preparation cell guaranteeing stable temperature and humidity. GISAXS was used for in situ monitoring of the time evolution of colloidal ordering within the whole illuminated sample area. The onset of ordering was indicated by the increase of integrated intensity within a small time frame shortly before complete evaporation of the dispersant. Single domains of coated samples were investigated ex situ by SAXS in transmission geometry where the irradiated sample area was 200 x 200 mu m(2) only. Domains with the typical size of a few millimeters were observed varying in orientation and crystallographic structure for various positions at the sample. They were mainly oriented along the grooves of the grating, confirming the influence of the underlying grating on colloidal ordering.
Y1  - 2009
UR  - http://pubs.acs.org/journal/langd5
U6  - https://doi.org/10.1021/La803078b
SN  - 0743-7463
ER  - 
TY  - JOUR
A1  - Reddy, Raghavendra V.
A1  - Gupta, Ajay
A1  - Gome, Anil
A1  - Leitenberger, Wolfram
A1  - Pietsch, Ullrich
T1  - In situ x-ray reflectivity and grazing incidence x-ray diffraction study of L1(0) ordering in Fe-57/Pt multilayers
N2  - In situ high temperature x-ray reflectivity and grazing incidence x-ray diffraction measurements in the energy dispersive mode are used to study the ordered face-centered tetragonal (fct) L1(0) phase formation in [Fe(19 angstrom)/ Pt(25 angstrom)](x10) multilayers prepared by ion beam sputtering. With the in situ x-ray measurements it is observed that (i) the multilayer structure first transforms to a disordered FePt and subsequently to an ordered fct L1(0) phase, (ii) the ordered fct L1(0) FePt peaks start to appear at 320°C annealing, (iii) the activation energy of the interdiffusion is 0.8 eV and (iv) ordered fct FePt grains have preferential out-of-plane texture. The magneto-optical Kerr effect and conversion electron Mossbauer spectroscopies are used to study the magnetic properties of the as- deposited and 400°C annealed multilayers. The magnetic data for the 400°C annealed sample indicate that the magnetization is at an angle of ~50° from the plane of the film.
Y1  - 2009
UR  - http://iopscience.iop.org/0953-8984
U6  - https://doi.org/10.1088/0953-8984/21/18/186002
SN  - 0953-8984
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Barberka, Thomas Andreas
A1  - Geue, Thomas
A1  - Stömmer, Ralph
T1  - X-ray scattering from thin organic films and multilayers
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
A1  - Smirnitzki, V.
A1  - Bugge, F.
T1  - Nondestructive analysis of a lateral GaAs nanostructure buried under AlGaAs using conventional high resolution and grazing incidence X-ray diffraction
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Stömmer, Ralph
A1  - Martin, C. R.
A1  - Geue, Thomas
A1  - Göbel, H.
A1  - Hub, W.
A1  - Pietsch, Ullrich
T1  - Comparative studies of fractal parameters of Si(100) surfaces measured by X-ray scattering and atomic force microscopy
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Stömmer, Ralph
A1  - Göbel, H.
A1  - Hub, W.
A1  - Pietsch, Ullrich
T1  - X-ray scattering from silicon surfaces
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Lübbert, Daniel
A1  - Pietsch, Ullrich
A1  - Zhuang, Y.
A1  - Zerlauth, S.
A1  - Bauer, Günther
T1  - In-plane strain and strain relaxation in laterally patterned Si/SiGe quantum dots and wire arrays
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Stahn, Jochen
A1  - Pucher, Andreas
A1  - Geue, Thomas
A1  - Daniel, A.
A1  - Pietsch, Ullrich
T1  - Electric field induced electron density response of GaAs and ZnSe
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Haier, P.
A1  - Herrmann, B. A.
A1  - Esser, N.
A1  - Pietsch, Ullrich
A1  - Lüders, K.
A1  - Richter, W.
T1  - Influence of the deposition rate on the structure of thin metal layers
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Pietsch, Ullrich
A1  - Wang, K. H.
A1  - Forchel, Alfred
A1  - Shen, W.
A1  - Kycia, S.
T1  - X-ray diffraction analysis of strain relaxation in free standing and buried GaAs/GaInAs/GaAs SQW lateral structures
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Grenzer, Jörg
A1  - Schomburg, E.
A1  - Lingott, I.
A1  - Ignotov, A. a.
A1  - Renk, K. F.
A1  - Pietsch, Ullrich
A1  - Rose, Dirk
A1  - Zeimer, Ute
A1  - Melzer, B. J.
A1  - Ivanov, S.
A1  - Schaposchnikov, S.
A1  - Kop'ev, P. S.
A1  - Pavel'ev, D. G.
A1  - Koschurinov, Yu.
T1  - X-ray and transport characterization of an Esaki-Tsu superlattice device
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Ulyanenkov, A.
A1  - Klemradt, U.
A1  - Pietsch, Ullrich
T1  - Investigation of strain relaxation in GaInAs/GaAs superlattices by x-ray diffuse scattering
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Darowski, Nora
A1  - Paschke, K.
A1  - Pietsch, Ullrich
A1  - Wang, K. H.
A1  - Forchel, Alfred
A1  - Lübbert, Daniel
A1  - Baumbach, Tilo
T1  - Structural characterization of a GaAs surface wire structure by triple-axis X-ray grazing incidence diffraction
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Englisch, Uwe
A1  - Penacorada, Florencio
A1  - Samoilenko, I.
A1  - Pietsch, Ullrich
T1  - Investigation of the vertical molecular exchange in a complex organic multilayer system
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Tsirelson, Vladimir G.
A1  - Abramov, Yury Fedorovich
A1  - Zavodnik, Valerie E.
A1  - Stash, Adam I.
A1  - Belokoneva, Elena L.
A1  - Stahn, Jochen
A1  - Pietsch, Ullrich
A1  - Feil, Dirk
T1  - Critical pionts in a crystal an procrystal
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Stahn, Jochen
A1  - Möhle, Marcus
A1  - Pietsch, Ullrich
T1  - Comparison of theoretical and experimental structure amplitudes of GaAs
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Penacorada, Florencio
A1  - Geue, Thomas
A1  - Pietsch, Ullrich
A1  - Brehmer, Ludwig
T1  - Monolayers and multilayers of uranyl arachidate : in-plane structure of uranyl arachidate multilayers
N2  - The molecular in-plane structure of uranyl arachidate Langmuir-Blodgett (LB) films formed at different subphase pH values was analysed by means of X-ray grazing-incidence diffraction. For multilayers formed at low subphase pH a reorganisation of the arachidic acid film structure is confirmed. At appropriate subphase pH values, reorganisation of the film structure, e.g. via the formation of three-dimensional crystallites, is prevented by the presence of the uranyl ions and by the subsequent introduction of conformational disorder (gauche defects) in the alkyl chains. The observation of a macroscopic flow-induced in-plane texture in these uranyl arachidate LB films has profound implications for the design of ordered, supramolecular structures by the Langmuir-Blodgett technique.
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Knochenhauer, Gerald
A1  - Dietel, Reinhard
A1  - Freydank, Anke-Christine
A1  - Zetzsche, Thomas
A1  - Pietsch, Ullrich
A1  - Brehmer, Ludwig
A1  - Barberka, Thomas Andreas
A1  - Geue, Thomas
T1  - Structure of thermally treated oxadiazoleamide Langmuir-Blodgett films
N2  - The thermal treatment of Y-type Langmuir-Blodgett (LB) films formed from the amphiphilic derivative of 2,5- diphenyl-1,3,4-oxadiazole 1 results in changes of the molecular packing. These changes have been analysed by a combination of X-ray specular reflectivity data, X-ray grazing incidence diffraction data and scanning force microscopy images, On the basis of these experimental data we have simulated possible supramolecular structures, These simulations provide insight into the intermolecular interactions giving rise to the observed structural transitions. The crystalline structure induced by thermal treatment of the LB films is characterized by a uniaxial texture, which is correlated with the dipping direction during deposition of the LB film.
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Avilov, Anatoly S.
A1  - Kulygin, Alexander K.
A1  - Pietsch, Ullrich
A1  - Spence, John C. H.
A1  - Tsirelson, Vladimir G.
A1  - Zuo, Ming J.
T1  - Scanning system for high-energy electron diffractometry
Y1  - 1999
UR  - http://www3.interscience.wiley.com/journal/118518709/home?CRETRY=1&SRETRY=0
U6  - https://doi.org/10.1107/S0021889899006755
SN  - 0021-8898
ER  - 
TY  - JOUR
A1  - Henneberg, Oliver
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Geue, Thomas
A1  - Finkelstein, Kenneth D.
T1  - Simultaneous X-ray and visible light diffraction for the investigation of surface relief and density grating formation in azobenzene containing polymer films
N2  - The development of surface relief and density patterns in azobenzene polymer films was studied by diffraction at two different wavelengths. We used x-ray diffraction of synchrotron radiation at 0.124 nm in combination with visible light diffraction at a wavelength of 633 nm. In contrast to visible light scattering x-ray diffraction allows the separation of a surface relief and a density grating contribution due to the different functional dependence of the scattering power. Additionally, the x-ray probe is most sensitive for the onset of the surface grating formation
Y1  - 2006
UR  - http://www.informaworld.com/smpp/title~content=t713644168~db=all
U6  - https://doi.org/10.1080/15421400500383345
SN  - 1542-1406
ER  - 
TY  - JOUR
A1  - Send, Sebastian
A1  - Abboud, Ali
A1  - Hartmann, Robert
A1  - Huth, M.
A1  - Leitenberger, Wolfram
A1  - Pashniak, N.
A1  - Schmidt, J.
A1  - Strüder, Lothar
A1  - Pietsch, Ullrich
T1  - Characterization of a pnCCD for applications with synchrotron radiation
JF  - Nuclear instruments & methods in physics research : a journal on accelerators, instrumentation and techniques applied to research in nuclear and atomic physics, materials science and related fields in physics ; A, Accelerators, spectrometers, detectors and associated equipment
N2  - In this work we study the response of a pnCCD by means of X-ray spectroscopy in the energy range between 6 key and 20 key and by Laue diffraction techniques. The analyses include measurements of characteristic detector parameters like energy resolution, count rate capability and effects of different gain settings. The limit of a single photon counting operation in white beam X-ray diffraction experiments is discussed with regard to the occurrence of pile-up events, for which the energy information about individual photons is lost. In case of monochromatic illumination the pnCCD can be used as a fast conventional CCD with a charge handling capacity (CHC) of about 300,000 electrons per pixel. If the CHC is exceeded, any surplus charge will spill to neighboring pixels perpendicular to the transfer direction due to electrostatic repulsion. The possibilities of increasing the number of storable electrons are investigated for different voltage settings by exposing a single pixel with X-rays generated by a microfocus X-ray source. The pixel binning mode is tested as an alternative approach that enables a pnCCD operation with significantly shorter readout times.
KW  - pnCCD
KW  - X-ray spectroscopy
KW  - X-ray imaging
KW  - Energy-dispersive Laue diffraction
Y1  - 2013
U6  - https://doi.org/10.1016/j.nima.2013.01.044
SN  - 0168-9002
VL  - 711
IS  - 5
SP  - 132
EP  - 142
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Send, Sebastian
A1  - Abboud, Ali
A1  - Leitenberger, Wolfram
A1  - Weiss, Manfred S.
A1  - Hartmann, Robert
A1  - Strüder, Lothar
A1  - Pietsch, Ullrich
T1  - Analysis of polycrystallinity in hen egg-white lysozyme using a pnCCD
JF  - Journal of applied crystallography
N2  - A crystal of hen egg-white lysozyme was analyzed by means of energy-dispersive X-ray Laue diffraction with white synchrotron radiation at 2.7 angstrom resolution using a pnCCD detector. From Laue spots measured in a single exposure of the arbitrarily oriented crystal, the lattice constants of the tetragonal unit cell could be extracted with an accuracy of about 2.5%. Scanning across the sample surface, Laue images with split reflections were recorded at various positions. The corresponding diffraction patterns were generated by two crystalline domains with a tilt of about 1 degrees relative to each other. The obtained results demonstrate the potential of the pnCCD for fast X-ray screening of crystals of macromolecules or proteins prior to conventional X-ray structure analysis. The described experiment can be automatized to quantitatively characterize imperfect single crystals or polycrystals.
Y1  - 2012
U6  - https://doi.org/10.1107/S0021889812015038
SN  - 0021-8898
VL  - 45
IS  - 6
SP  - 517
EP  - 522
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
T1  - X-ray reflectivity from sinusoidal surface relief gratings
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
T1  - Reversible negative thermal expansion of polymer films
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Poloucek, P.
A1  - Pietsch, Ullrich
A1  - Geue, Thomas
A1  - Symietz, Christian
A1  - Brezesinski, Gerald
T1  - X-ray reflectivity analysis of thin complex Langmuir-Blodgett films
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Stahn, Jochen
A1  - Pietsch, Ullrich
A1  - Blaha, Pawel
A1  - Schwarz, K. H.
T1  - Electric field induced charge-density variations in covalently bonded compounds
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Stahn, Jochen
A1  - Davaasambuu, Jav
A1  - Pucher, Andreas
T1  - Electric field induced charge density variations in partially-ionic compounds
Y1  - 2001
SN  - 0022-3697
ER  - 
TY  - JOUR
A1  - Davaasambuu, Jav
A1  - Daniel, A.
A1  - Stahn, Jochen
A1  - Pietsch, Ullrich
T1  - Harmonic and anharmonic thermal vibrations in cubic ZnSe
Y1  - 2001
SN  - 0044-2968
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Zeimer, Ute
A1  - Hofmann, L.
A1  - Grenzer, Jörg
A1  - Gramlich, S.
T1  - Strain induced compositional modulations in AlGaAs overlayers induced by lateral surface gratings
Y1  - 2001
SN  - 0272-9172
ER  - 
TY  - JOUR
A1  - Davaasambuu, Jav
A1  - Daniel, A.
A1  - Stahn, Jochen
A1  - Pietsch, Ullrich
T1  - Comparison of experimental and theoretical valence charge densites in cubic ZnSe
Y1  - 2001
SN  - 0022-3697
ER  - 
TY  - JOUR
A1  - Avilov, Anatoly S.
A1  - Lepeshov, G. G.
A1  - Pietsch, Ullrich
A1  - Tsirelson, Vladimir G.
T1  - Multipole analysis of the electron density and electrostatic potential in Germanium by high-resolution electron diffraction
Y1  - 2001
SN  - 0022-3697
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Grenzer, Jörg
A1  - Geue, Thomas
A1  - Neißendorfer, Frank
A1  - Brezesinski, Gerald
A1  - Symietz, Christian
A1  - Möhwald, Helmuth
A1  - Gudat, Wolfgang
T1  - The energy dispersive reflectometer at BESSY II : a challenge for thin film analysis
Y1  - 2001
SN  - 0167- 5087
ER  - 
TY  - JOUR
A1  - Zeimer, Ute
A1  - Bugge, F.
A1  - Gramlich, S.
A1  - Smirnitzki, V.
A1  - Weyers, Markus
A1  - Tränkle, G.
A1  - Grenzer, Jörg
A1  - Pietsch, Ullrich
A1  - Cassabois, G.
A1  - Emiliani, V.
A1  - Linau, Christoph
T1  - Evidence of strain-induced lateral carrier confinement in InGaAs-quantum wells by low-temperature near-field spectroscopy
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Zeimer, Ute
A1  - Grenzer, Jörg
A1  - Pietsch, Ullrich
A1  - Bugge, F.
A1  - Smirnitzki, V.
A1  - Weyers, Markus
T1  - Investigation of strain-modulated InGaAs-nanostructures by grazing-incidence x-ray diffraction and photoluminescence
Y1  - 2001
ER  -