Dominant paramagnetic centers in ¹⁷O-implanted diamond

Electron spin resonance (ESR) measurements were performed on nitrogen-free diamond films grown by chemical vapor deposition and on diamond single crystals, irradiated by ¹⁷O ions and annealed in the temperature range 100–1400 °C. For those annealed in the range 700–1050 °C, the spectra are dominated by the R5, O1, R6, R10, R11, and KUL11 centers. Analysis of both single-crystal and powder-pattern ESR spectra allowed us to trace ¹³C hyperfine interaction structure and to deduce accurate values of the spin Hamiltonian parameters for those centers. Interpretation of those values confirms the previous suggestion that the R5, O1, R6, R10, R11, and KUL11 centers may originate from 〈110〉 chains of three, four, five, six, seven, and eight vacancies, respectively. Those centers disappear after annealing at 1150 °C to uncover an S=1/2 center, labeled KUL12, with a resolved ¹⁷O hyperfine structure.