Doped Synthetic Diamonds—Anomalous X-ray Spikes Along <III>

Abstract

Lonsdale and Smith¹ showed that type I natural diamonds give anomalous X-ray diffraction scattering along <100> directions in reciprocal space. Hoerni and Wooster² explained the intensities of this phenomenon in terms of impurity atoms in {100} planes, these impurity atoms having a scattering power not much different from that of carbon. Kaiser and Bond³ published data, based on residual gas analyses, indicating that type I (infra-red opaque) diamonds (but not the transparent type II) contain up to 0.23 per cent of nitrogen-14, the amount being proportional to the intensity of the 7.8µ absorption band. They did not, however, attempt to correlate the quantity of nitrogen-14 present with the intensity (or indeed the presence) of X-ray extra spikes in the diamonds they used. Nor was this correlation made by Evans and Phaal⁴, who obtained from type I (infra-red opaque) diamonds elegant transmission electron micrographs which show the presence of {100} impurity platelets, the impurity being assumed to be nitrogen.