Observation of Oriented Close-Packed Lattice Planes in Polycrystalline Hard-Sphere Solids.
We report time-resolved Bragg scattering experiments on solidifying colloidal suspensions of hard spheres. The polar angle-averaged, integrated intensity of the (111) and (311) reflections show a transient, two-step behavior below melting, which depends in a complex way on the volume fraction and is not present for (200) or (220). Detailed analysis of the full two-dimensional scattering pattern reveals intensity maxima of sixfold symmetry close to the position of the (111) and (311) Debye-Scherrer rings. These can be explained assuming oriented crystals with close-packed planes parallel to the container walls. We show that the observed temporal behavior is due to competing homogeneous and heterogeneous nucleation and growth scenarios. Copyright 1998 Academic Press.
Institut für Physik der, Johannes-Gutenberg-Universität, Staudingerweg 7, Mainz, 55099, Germany
A
Heymann
A
Stipp
C
Sinn
T
Palberg