1. Scattering Experiments

2. Coherence Length
Structural coherence length found for small regions from TEM images
SAXS: Structural Lcoh average
SANS: Structural and Magnetic Lcoh averages

3. Small Angle X-ray Scattering
Bragg’s Law
Observe diffraction from planes of particles at small angles
Both the lattice symmetry and the shape of diffracting object contribute to the intensity I(q)
Ignore scattering by the surfactant coating
 the radius R = Rcore

4. 3D Arrays Structures from SAXS
x=10.3 nm
Shape factor, d=8.5 nm -2
d=8.5 nm -4 -6 -8
Shcp(q)P(q)
Both hcp and fcc arrays observed
Shcp(q)P(q)

5. 3D Arrays Made Over 4 Weeks
Interparticle spacing slightly reduced
x=9.6 nm
d=8.5 nm
Average intensity
Sharpest peak
Spots due to 3 hcp supercrystals- Large Lcoh

6. Nanoparticle Crystals vs Disordered Assemblies
SAXS patterns of 8.5 nm Fe nanoparticle FCC nanoparticle crystals and rapidly quenched assemblies

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