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Novosibirsk, Russia

Vins V.G.,Institute of Single Crystals Ltd. | Yelisseyev A.P.,RAS Institute of Geology and Mineralogy | Lobanov S.S.,RAS Institute of Geology and Mineralogy | Afonin D.V.,Institute of Single Crystals Ltd. | And 2 more authors.
Diamond and Related Materials | Year: 2010

Experimental results of APHT (atmospheric pressure high temperature) treatment of dark brown type Ia natural diamonds are discussed. The APHT treatment was carried out under the atmospheric pressure using an experimental homemade system. The samples were placed in the inert gas current and subjected to 5 or 6 repeated thermal shocks, i.e. the diamonds were sharply heated to 1300-2100 °C. As a result, the original brown color of the samples was considerably reduced. The IR absorption intensity of the main A and B nitrogen centers was not observed to change. However, photoluminescence due to N3 and H3 centers was observed in the treated samples. © 2010 Elsevier B.V. All rights reserved. Source


Yelisseyev A.P.,RAS Institute of Geology and Mineralogy | Vins V.G.,Institute of Single Crystals Ltd. | Lobanov S.S.,RAS Institute of Geology and Mineralogy | Afonin D.V.,Institute of Single Crystals Ltd. | And 2 more authors.
Journal of Crystal Growth | Year: 2011

Possible mechanisms of aggregation of donor nitrogen (C center) into a pair of nitrogen atoms (A center) in Ni-containing synthetic diamonds with NV centers subjected to high temperature annealing without external pressure are discussed. It was shown that the activation energy of aggregation varied from 0.5 to 1.5 eV depending on nitrogen concentration. This can be due to three different aggregation mechanisms taking place at the same time. The formation of isolated vacancies and nitrogen interstitials was studied in electron-irradiated diamonds containing different concentrations of donor nitrogen. © 2010 Elsevier B.V. All rights reserved. Source

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