Identification of paramagnetic nitrogen centers (P1) in diamond crystallites synthesized via the sintering of detonation nanodiamonds at high pressure and temperature

摘要: Diamond single crystals synthesized from powder detonation nanodiamonds (DNDs) by means of treatment at high pressures (P ~ 7 GPa) and temperatures (T > 1300°C) have been studied electron paramagnetic resonance (EPR). A key feature (high-pressure high–temperature (HPHT) sintering) is the use low molecular weight alcohols in process. The appearance a hyperfine EPR signal structure due to “paramagnetic nitrogen” (P1 centers) explained growth submicron micron diamond DND nanocrystals oriented attachment coalescence mechanism. Such coarsening appreciably decreases concentration centers, presence which hinders detection P1 near-surface areas coalesced grown together particles. It has shown that defects all types ~3.1 × 1018 g–1 (~60 ppm) during HPHT T = 1650°C. This causes successful identification whose fraction no less than ~40% total amount centers microcrystals sintering.