High-Quality Synthetic Diamond Crystals.

Abstract

High-quality synthetic type IIa diamond crystals of several carats, containing less than 0.1 ppm chemical impurities and few inclusions, have been successfully synthesized by the temperature gradient method under high pressure and high temperature. The crystals are transparent over a wide range of wavelengths from ultraviolet to far infrared regions, showing no absorptions due to impurities.They also have high crystalline quality with fewer crystal defects, less internal strain, and less variation in defects among crystals than those of natural diamonds or conventional synthetic type Ib diamond. The outstanding characteristics of the synthetic type IN diamond permit application to a considerably wide range of industrial and scientific uses such as optical parts, monochromators, high-pressure anvils, and so on.[synthetic diamond, high pressure, crystal growth, impurity, dislocation]

Synthesis and Phase Transition of HgTiO3

“…HgTiO 3 powder was loaded into a diamond-anvil cell designed by R. Miletich et al, which is optimized for X-ray diffraction measurements using an IP detector to obtain low-background images. Details was given by R. Miletich et al [2][3][4]. Differential scanning calorimetry (DSC) measurements were performed on a MAC Science Co., Ltd. analyzer DSC3200S.…”

High-Pressure Single-Crystal Techniques

“…Type-I diamonds contain significant amounts of nitrogen impurity (0.1 at % or more) and are further classified into groups A and B depending on how the nitrogen impurities aggregate. The diamonds classified as type-II do not contain significant nitrogen impurity, although they do contain traces of a variety (b) IR spectra (after Sumiya et al 1998). of impurities at the parts per million level, and are further classified into groups A and B depending on their electrical conductivity. As type-II diamonds do not show absorption bands in the ultraviolet and infrared regions (Fig.…”

“…For the high-temperature module (Fig. 51) the beryllium discs are replaced by conically shaped 7 × 2 mm single-crystal diamond backing plates, made from synthetic diamonds (Sumiya et al 1998). These backing plates are placed onto tungsten carbide seats and, being transparent, do not require optical access holes.…”

Trapiche Tourmaline From Zambia

“…Evidence for rapid growth rates can be seen in snowflakes, which can show all stages from normal hexagonal growth to entirely dendritic growth (Libbrecht and Rasmussen, 2003). The channels were formed by rapid growth and the associated black inclusions were trapped in the tourmaline at the faster-growing edges, since a rapid growth rate is one factor that causes more inclusions to be trapped within a gem (Nassau and Jackson, 1970;Sumiya et al, 2005). The accumulation of black inclusions on the faces of the core formed by the {101 -1} sector is likely related to a change in growth conditions.…”