Cobalt impurities in synthetic diamond

• Published in: Diamond and related materials 1999-10, Vol.8 (10), p.1895-1899
• Main Authors: Jia, X., Hayakawa, S., Li, W., Gohshi, Y., Wakatsuki, M.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Diamond; Exact sciences and technology; Impurities: concentration, distribution, and gradients; Impurity and growth sector; Impurity concentration, distribution, and gradients; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Structure of solids and liquids; crystallography; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; X-ray fluorescence
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/S0925-9635(99)00164-8

High-quality single crystals of diamond were grown by the temperature-gradient method using cobalt-containing metals as the solvent-catalyst. Cobalt and nickel impurities in the crystals were measured by X-ray fluorescence using synchrotron radiation. Their distributions were imaged by a mapping technique. Their concentrations were also measured at a number of points of the crystals. X-ray absorption near edge structure (XANES) spectroscopic measurements were carried out to investigate the bonding nature of the impurities. It was confirmed that the cobalt impurity distributes preferentially in the {111} sectors like nickel. We found that the concentration of cobalt is in proportional correlation with that of nickel in crystals grown from alloys containing both cobalt and nickel, and that cobalt is more difficult to incorporate than nickel. The XANES measurements revealed that the cobalt impurity occupies tetrahedral sites like nickel.