Fourier-transform and continuous-wave EPR studies of nickel in synthetic diamond: Site and spin multiplicity

Pulsed, Fourier-transform, and continuous-wave electron paramagnetic resonance methods are used to study the g=2.0319 EPR signal in synthetic diamond crystals. This signal is from Ni which is found to be located at a substitutional site in the diamond lattice without detectable nearby charge compensation. The effective spin state of S=(3/2 is determined from Fourier-transform nutational EPR spectroscopy. It is proposed that the center is a ${\mathrm{Ni}}^{\mathrm{-}}$ ion with electronic configuration 3${\mathit{d}}^7$.