Time-resolved X-ray diffraction studies of phonons and phase transitions
Author
Summary, in English
This thesis summarizes work in which time-resolved X-ray diffraction has been used to probe crystalline materials, thereby revealing the dynamics of phonons and phase transitions.
X-ray diffraction is the standard tool in investigations of structure on the atomic scale. It has been used for a long time, and has successfully helped scientists to find the structure of a wide range of materials. The use of ultrafast time-resolved X-ray diffraction is a strongly emerging field which is still under development.
Impulsive strain pulses, or coherent acoustic phonons, have been probed using optical techniques for at least two decades. Yet, optical pulses can only probe the surface of a semiconductor. X-rays penetrate deeper and can follow the phonons as they propagate into the sample.
Real time studies of phase transitions have also been conducted using optical methods. These measurements are indirect in the sense that they probe the susceptibility change of the sample rather than the positions of the atoms. Again, time-resolved X-ray diffraction can give new insights into the field by probing the structural changes directly.
This thesis focuses mainly on experimental work in which time-resolved X-ray diffraction has been used to probe phonons or samples undergoing phase transitions. A brief theoretical background will also be given, as well as a description of beamline D611 at MAX-lab, a synchrotron beamline for time-resolved X-ray diffraction measurements which has been developed during the work for this thesis.
X-ray diffraction is the standard tool in investigations of structure on the atomic scale. It has been used for a long time, and has successfully helped scientists to find the structure of a wide range of materials. The use of ultrafast time-resolved X-ray diffraction is a strongly emerging field which is still under development.
Impulsive strain pulses, or coherent acoustic phonons, have been probed using optical techniques for at least two decades. Yet, optical pulses can only probe the surface of a semiconductor. X-rays penetrate deeper and can follow the phonons as they propagate into the sample.
Real time studies of phase transitions have also been conducted using optical methods. These measurements are indirect in the sense that they probe the susceptibility change of the sample rather than the positions of the atoms. Again, time-resolved X-ray diffraction can give new insights into the field by probing the structural changes directly.
This thesis focuses mainly on experimental work in which time-resolved X-ray diffraction has been used to probe phonons or samples undergoing phase transitions. A brief theoretical background will also be given, as well as a description of beamline D611 at MAX-lab, a synchrotron beamline for time-resolved X-ray diffraction measurements which has been developed during the work for this thesis.
Department/s
Publishing year
2005
Language
English
Publication/Series
Lund Reports in Atomic Physics
Volume
LRAP-350
Full text
Document type
Dissertation
Publisher
Department of Physics, Lund University
Topic
- Atom and Molecular Physics and Optics
Keywords
- Fysik
- Physics
- Phase transitions
- X-ray diffraction
- Phonons
Status
Published
Supervisor
ISBN/ISSN/Other
- ISSN: 0281-2762
- ISBN: 91-628-6662-1
Defence date
2 December 2005
Defence time
13:15
Defence place
Room B, Department of Physics, Professorsgatan 1, Lund Institute of Technology
Opponent
- Robert Schoenlein (Dr)