Inhalt

•  
   Introduction
•  
  Theoretical Background
•  
   Magnetism
•  
   Forms of magnetism
•  
   Magnetism on nanoscales
•  
  Formation of nanoparticles
•  
   Wet chemical approach
•  
   Kinetical description of particle formation
•  
   Thermodynamical description of particle formation
•  
  Synthesis of cobalt nanoparticles and oxidation
•  
   Synthesis of nanoparticles
•  
   Purification
•  
   Surfactants and surfactant exchange
•  
   Surfactants
•  
   Surfactant exchange
•  
   Stabilization
•  
  Oxidation
•  
   Oxidation of nanoparticles
•  
   Mathematical description of the oxidation process
•  
  Devices
•  
   TEM
•  
   SEM
•  
  STEM
•  
   Image modes
•  
   Lens aberrations
•  
   EDX
•  
  FIB
•  
   LMIS
•  
   Interactions of electrons and ions with the sample
•  
   Ion etching and sputtering
•  
   Gas assisted ion beam etching
•  
   Gas assisted ion beam deposition
•  
   Sample manipulation with the micromanipulator
•  
   XRD
•  
  AGM
•  
   Function of an AGM
•  
   Low temperature setup
•  
   IR-spectroscopy
•  
   Nanoparticles - characteristics
•  
   Cobalt nanoparticles - overview
•  
   Shape
•  
   Crystallinity of Co particles
•  
   Oxidation of particles prepared with different surfactants
•  
  Surfactants and surfactant exchange
•  
   Basic particles prepared with trioctylphosphin oxide (TOPO)
•  
   Surfactant exchange
•  
   Used surfactants
•  
   Amine group as head molecule
•  
   Carboxyl group as head molecule
•  
   Size reduction
•  
   Inter particle distance
•  
   Convolution of the surfactant molecules
•  
   Change of magnetic properties
•  
   Comparison - surfactant exchange on TOPO particles
•  
   Basic particles prepared with oleylamine
•  
   Used surfactants and size reduction
•  
   Conclusion for self-assembly changes by surfactant exchange
•  
   Change of magnetic properties
•  
   Conclusion
•  
   Oxidation at room temperature
•  
   Calculation of the effective magnetic particle volume and radius
•  
   Second surfactant exchange on TOPO
•  
   Surfactant exchange based on oleylamine
•  
   Conclusion
•  
  Temperature dependence
•  
   Particles stored at a temperature of -18C
•  
   Particles stored at a temperature of 48C
•  
   Particles stored at a temperature of 80C
•  
   Particles stored at a temperature of 121C
•  
   Particles stored at a temperature of 180C
•  
   Particles stored at a temperature of 300C
•  
   Conclusion
•  
   Temperature effects on crystallinity and shape
•  
  Oxidation measurements during the first 30 minutes after fabrication
•  
   AGM oxidation setup
•  
   Used surfactants
•  
   Effects of the surfactant exchange
•  
   Magnetic properties
•  
   Oxidation during the first thirty minutes after fabrication
•  
   Conclusion
•  
   Crystallinity of particles
•  
   Oxide shells - conclusion
•  
  Oxidation behaviour in dependence on shape
•  
   Measurements
•  
   Finite elements simulation
•  
   Volume consideration
•  
   Conclusion
•  
   Discussion
•  
   Oxidation of nanoparticle clusters
•  
   Older Particles
•  
   Newer Particles
•  
  Effective oxygen diffusion in clusters
•  
   Oxygen diffusion process in the case of one nanoparticle
•  
   Oxidation process in the case of nanoparticle clusters
•  
   Conclusion
•  
   Summary
•  
  Conference Contributions
•  
   Publications