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Time-resolved X-ray diffraction studies of phonons and phase transitions

Synnergren, Ola LU (2005) In Lund Reports in Atomic Physics LRAP-350.
Abstract (Swedish)
Popular Abstract in Swedish

Denna avhandling sammanfattar arbete där tidsupplöst röntgendiffraktion har använts för att undersöka kristallina material och studera dynamiken hos fononer och fasövergångar.



Röntgendiffraktion är standardverktyget för stukturbestämning på en atomär skala. Det har använts länge och har framgångsrikt hjälp vetenskapsmän att bestämma strukturen hos en stor mängd material. Användningen av ultrasnabb tidsupplöst röntgendiffration är ett starkt växande område som fortfarande utvecklas.



Akustiska impulser, eller koherenta akustiska fononer, har studerats med hjälp av optiska tekniker i åtminstonde två årtionden. Optiska pulser kan dock endast underöka en... (More)
Popular Abstract in Swedish

Denna avhandling sammanfattar arbete där tidsupplöst röntgendiffraktion har använts för att undersöka kristallina material och studera dynamiken hos fononer och fasövergångar.



Röntgendiffraktion är standardverktyget för stukturbestämning på en atomär skala. Det har använts länge och har framgångsrikt hjälp vetenskapsmän att bestämma strukturen hos en stor mängd material. Användningen av ultrasnabb tidsupplöst röntgendiffration är ett starkt växande område som fortfarande utvecklas.



Akustiska impulser, eller koherenta akustiska fononer, har studerats med hjälp av optiska tekniker i åtminstonde två årtionden. Optiska pulser kan dock endast underöka en halvledares yta. Röntgen penetrerar djupare in i proven och kan följa fononer då de färdas in i proven.



Realtidsstudier av fasövergångar har också utförts med hjälp av optiska metoder. Dessa mätningar är indirekta då de mäter ändringar i susceptibiliteten hos provet istället för atomernas positioner. Återigen kan tidsupplöst röntgendiffraktion ge en ny insyn i området genom att den gör en direkt mätning av de strukturella ändringarna.



Den här avhandlingen fokuserar huvudsaklingen på experimentellt arbete där tidsupplöst röntgendiffraktion använts för att studera fononer eller prover som genomgår en fasövergång. En kort teoretisk bakgrund finns med, liksom en beskrivning av D611, ett synkrotronljusstrålrör för tidsupplöst röntgendiffraktion som utvecklats under arbetet med den här avhandlingen. (Less)
Abstract
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... (More)
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. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr Schoenlein, Robert, Lawrence Berkeley National Laboratory
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Fysik, Physics, Phase transitions, X-ray diffraction, Phonons
in
Lund Reports in Atomic Physics
volume
LRAP-350
pages
140 pages
publisher
Department of Physics, Lund University
defense location
Room B, Department of Physics, Professorsgatan 1, Lund Institute of Technology
defense date
2005-12-02 13:15
ISSN
0281-2762
ISBN
91-628-6662-1
language
English
LU publication?
yes
id
a83aac81-5416-47ba-9f03-bf3ec1f95efc (old id 545638)
date added to LUP
2007-10-02 15:46:21
date last changed
2016-09-19 08:44:56
@phdthesis{a83aac81-5416-47ba-9f03-bf3ec1f95efc,
  abstract     = {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.<br/><br>
<br/><br>
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.<br/><br>
<br/><br>
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.<br/><br>
<br/><br>
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.<br/><br>
<br/><br>
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.},
  author       = {Synnergren, Ola},
  isbn         = {91-628-6662-1},
  issn         = {0281-2762},
  keyword      = {Fysik,Physics,Phase transitions,X-ray diffraction,Phonons},
  language     = {eng},
  pages        = {140},
  publisher    = {Department of Physics, Lund University},
  school       = {Lund University},
  series       = {Lund Reports in Atomic Physics},
  title        = {Time-resolved X-ray diffraction studies of phonons and phase transitions},
  volume       = {LRAP-350},
  year         = {2005},
}