X-ray Imaging and Spectroscopy of

1
X-ray Imaging and Spectroscopy of Individual
Nanoparticles
A. Fraile Rodríguez, F. Nolting Swiss Light
Source Paul Scherrer Institut, Switzerland
J. Bansmann Dept of Surface Chemistry and
Catalysis Universität Ulm, Germany A.
Kleibert Institut für Physik, Universität
Rostock, Germany U. Wiedwald Dept of Solid State
Physics Universität Ulm, Germany
2
(No Transcript)
3
Superparamagnetism
4
(No Transcript)
5

• Single Particle experiments
• Correlate the electronic, magnetic and structural
  properties with the size, aspect ratio,
  crystalline structure, and chemical composition
  of each individual particle.
• The ability to manipulate a single nanoparticle
  has an increased potential in device manufacturing

6
Single Particle Detection Techniques Available
Technique ?x (nm) E-resolution (eV)
SP-STM 0.5 lt 0.2
EELS 0.5 0.5
Optical Fluorescence lt 5 0.02
Technique ?x (nm) System (Individual Particles)
XPEEM 50 InAs (D50 nm), ?E/E0.2 eV, Heun et al. Fe2O3 (D 10 nm), ?E/E0.5 eV, Rockenberger et al.
7
chemical bonding electronic properties
8
Soft x-ray Spectromicroscopy
Element specific imaging PEEM
Co
Py
Substrate
Co islands, 778.1 eV
Py film, 852.7 eV
5 ?m
9
X-ray PhotoEmission Electron Microscopy

• probing secondary/Auger/photoemission
• spatial resolution 50 nm
• electron energy resolution 0.1 eV
• HA 30 mT
• 100 K lt T lt 1500 K
• ultra high vacuum

10
(No Transcript)
11
Particle Size Scanning Electron Microscopy
Co particles, Al capping layer
Co particles, no capping layer
D 10 nm
D 8 nm

• deposition of Co particles on Si substrates
• coverage 5-10 particles/?m2
• lithographic markers on substrates
• low percentage dimers/trimers
• crystalline structure

Lithographic markers L. J. Heyderman, PSI
12
Elemental Contrast X-ray PEEM
Co particles D ? 13 nm oxidized in air
13
(No Transcript)
14
Individual Particles X-ray Absorption Spectra
Co particles D ? 8 nm, no capping layer
770 775 780 790 795 800 805
810
Photon Energy (eV)
Movie 159 images Total acquisition time 12
hours.
15
(No Transcript)
16
(No Transcript)
17

• alloy systems, e.g. FexCo1-x , FexPt1-x
• Magnetic transition temperatures on the nanoscale

18
Conclusions
19
Collaborators
F. Nolting, Swiss Light Source Paul Scherrer
Institut, Switzerland
J. Bansmann, Dept of Surface Chemistry and
Catalysis Universität Ulm, Germany A.
Kleibert, Institut für Physik, Universität
Rostock, Germany U. Wiedwald, Dept. Solid State
Physics, Universität Ulm, Germany L. J.
Heyderman,Laboratory for Micro- and
Nanotechnology Paul Scherrer Institut,
Switzerland