Entwicklung eines hochauflösenden Röntgen-Einkristalldiffraktometers und Strukturuntersuchungen an La 2 - x Sr x CuO 4 - Einkristallen
type: CreativeWork
description: The first part of this thesis describes the development of a new high resolution x-ray single crystal diffractometer (RED) and its multiple applications. It is shown that the application of the presently available technologies allows very flexible and even completely new possibilities of structural investigations of single crystals with x-rays in laboratories. The quick exchange between different beam optics allows flexible and efficient scientific work. Available are standard optics for Bragg data collection (Cu-K_alpha- and Mo-K_alpha radiation), an additional secondary monochromator unit for pure elastic scattering experiments and a Ge-fourfold monochromator for high resolution measurements using pure Cu-K_alpha_1 radiation. The standard optics allow in combination with the large dynamical ranges (max. 500.000 cps linear) of the available detectors detailed investigations of structures with extreme differences between integrated intensities. Furthermore, detailed temperature dependent measurements can be performed down to 20 K by using an additional closed-cycle cryostat, e.g. for structural investigations at phase transitions. The Ge-fourfold monochromator yields high resolutions comparable to those of similar instruments at synchrotron sources (e.g. Si-(111) reflection with a halfwidth of < 0.0030°, Rocking scan). This allows a very precise analysis of reflection profiles for characterization of sample quality and the observation of smallest structural distortions. On principle the available radiation intensity of the RED is significantly smaller than that of a synchrotron. Nevertheless measurements of several samples show that the flexibility of the RED yields scientific possibilities for structural investigations at the home laboratory which are normaly available only at synchrotron facilities. The second part of this work describes structural investigations with neutron diffraction of strontium doped lanthanium cuprate La(2-x)Sr(x)CuO4 (LSCO), a high-tempera…
abstract: The first part of this thesis describes the development of a new high resolution x-ray single crystal diffractometer (RED) and its multiple applications. It is shown that the application of the presently available technologies allows very flexible and even completely new possibilities of structural investigations of single crystals with x-rays in laboratories. The quick exchange between different beam optics allows flexible and efficient scientific work. Available are standard optics for Bragg data collection (Cu-K_alpha- and Mo-K_alpha radiation), an additional secondary monochromator unit for pure elastic scattering experiments and a Ge-fourfold monochromator for high resolution measurements using pure Cu-K_alpha_1 radiation. The standard optics allow in combination with the large dynamical ranges (max. 500.000 cps linear) of the available detectors detailed investigations of structures with extreme differences between integrated intensities. Furthermore, detailed temperature dependent measurements can be performed down to 20 K by using an additional closed-cycle cryostat, e.g. for structural investigations at phase transitions. The Ge-fourfold monochromator yields high resolutions comparable to those of similar instruments at synchrotron sources (e.g. Si-(111) reflection with a halfwidth of < 0.0030°, Rocking scan). This allows a very precise analysis of reflection profiles for characterization of sample quality and the observation of smallest structural distortions. On principle the available radiation intensity of the RED is significantly smaller than that of a synchrotron. Nevertheless measurements of several samples show that the flexibility of the RED yields scientific possibilities for structural investigations at the home laboratory which are normaly available only at synchrotron facilities. The second part of this work describes structural investigations with neutron diffraction of strontium doped lanthanium cuprate La(2-x)Sr(x)CuO4 (LSCO), a high-tempera…
author: Meven, Martin
language: ger
keywords: info:eu-repo/classification/ddc/550, Cuprate, Hochtemperatursupraleiter, Lanthanverbindungen, Neutronendiffraktometrie, Röntgendiffraktometer, Strontiumverbindungen, Geowissenschaften
date published: 2001
date modified: 2026-07-30T19:43:28Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University