Diffraction contrast from precipitates in type I diamonds

Abstract

Using the dynamical theory of electron diffraction, profiles have been computed for the electron microscope images of impurity platelets found in the cube planes of type I diamonds. Following a procedure described in two recent papers by Ashby and Brown, estimates have been made of the relative displacements of the lattices on either side of the platelets in four diamonds. It is suggested that the platelets contain a varying number of nitrogen-rich planes and that each impurity plane produced a lattice displacement of approximately 1a/6, where a is the (400) interplanar spacing. The diamond lattice on either side of the platelets is in compression and some strain has been detected in the plane of the platelets.