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High-resolution small-angle x-ray diffraction study of long-range order in hard-sphere colloidal crystals.
A V Petukhov1, D G A L Aarts, I P Dolbnya
1van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, University of Utrecht, Padualaan 8, 3508 TB Utrecht, The Netherlands. a.v.petukhov@chem.uu.nl
Physical Review Letters
|May 15, 2002
Summary
Researchers studied colloidal sphere crystals using synchrotron X-ray diffraction. They found long-range order extending over 500 planes, with precise orientation but random stacking of hexagonal planes.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Colloid Science
Background:
- Colloidal crystals are model systems for studying phase transitions and order in matter.
- Understanding long-range order is crucial for designing materials with specific properties.
Purpose of the Study:
- To determine the long-range order parameters in hard colloidal sphere crystals.
- To investigate the extent of positional and orientational order in these crystals.
Main Methods:
- Synchrotron small-angle X-ray diffraction (SAXRD) was employed.
- High resolution (10^-6 of the wave vector) was used to analyze lattice reflections.
Main Results:
- Positional order extends over at least 500 lattice planes.
- Lattice planes exhibit orientational correlation within 0.1 degrees.
- Stacking of hexagonal planes was found to be random.
Conclusions:
- Colloidal sphere crystals exhibit significant long-range positional and orientational order.
- The random stacking of hexagonal planes suggests specific growth dynamics or defect structures.