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.
Heymann
A
Institut für Physik der, Johannes-Gutenberg-Universität, Staudingerweg 7, Mainz, 55099, Germany
Stipp
A
Sinn
C
Palberg
T