Electron Spin Resonance in Neutron-Irradiated Diamond

A comprehensive study has been made of electron spin resonance in neutron-irradiated diamond. The main feature is the A spectrum, a broad intense line centered at g = 2.00. The concentration of A centers is proportional to dose for doses up to 5 × 1019 n0 cm−2, when the concentration is 1021 centers cm−3. At least three centers contribute to the A spectrum. The anisotropic B and C spectra are observed in specimens irradiated to doses less than 1019 n0 cm−2. The anisotropic spectrum D is shown to be an annealing product. The spin Hamiltonian is [Formula: see text] either with D = (1.04 ± 0.01) × 10−2 cm−1, E = (2.7 ± 0.2) × 10−4 cm−1, S = 1, g = 2.00 or D = 0.52 × 10−2 cm−1, E = 1.3 × 10−4 cm−1, S = 3/2, g = 2.00. The A, B, and C spectra have been observed in electron-irradiated diamond by Owen. The models proposed here are in broad agreement with his proposals.