Structure and creation conditions of complex nitrogen-nickel defects in synthetic diamonds

Incorporation of Large Impurity Atoms into the Diamond Crystal Lattice: EPR of Split-Vacancy Defects in Diamond

“…A lattice expansion was detected in diamond with increasing nitrogen concentration, and it was concluded that nitrogen presumably formed substitutional defects. The maximum concentration of the nitrogen impurity in type I diamond detected by mass spectrometry was~10 20 cm −3 . After the comparison [4] of the IR and UV absorption spectra with the electron paramagnetic resonance (EPR) spectra, type I diamonds were also subdivided into two groups.…”

“…At the same time, the HPHT annealing procedure of diamonds was elaborated in detail. Using these new techniques, diamond crystals were synthesized in the Fe-Ni-C and Ni-C systems in Novosibirsk, Russia [19][20][21][22]. The P1 and W8 centers were observed in the EPR spectra of diamond crystals synthesized at a temperature of 1700 K and a pressure of 5.5 GPa.…”

“…Table 1. Parameters of the spin Hamiltonian for different nickel-containing centers with S = 1/2 in diamond [19][20][21][22]. The directions are for a C 2h symmetry site with (1-10) as its plane of reflection symmetry.…”

Crystal Growth of Diamond

“…The impurities have been detected by ESR and EPMA techniques [46,68,69] with concentrations up to 70 ppm. The ESR analysis has concluded that the nickel atoms sit on substitutional and interstitial sites [69,70], and that they are present as complexes, labeled NE1, NE2, etc, of nickel, nitrogen and vacancies [71,72]. A number of absorption and luminescence bands related to nickel impurities have been recorded [73][74][75].…”

“…The color change may be due to aggregation of nickel and nitrogen impurities. ESR measurements have proposed a complex structural model consisting of a nickel atom, nitrogen atoms and vacancies [71,72].…”