THE DEPENDENCES OF ESR LINE WIDTHS AND SPIN-SPIN RELAXATION-TIMES OF SINGLE NITROGEN DEFECTS ON THE CONCENTRATION OF NITROGEN DEFECTS IN DIAMOND

Line widths and spin-spin relaxation times of P1 centres in synthetic Ib and natural la diamonds with concentrations of P1 and P2 centres co vering the range 0.03-400 atomic parts per million have been measured. At concentrations higher than about ten atomic parts per million the line width is linearly dependent on the concentration. At lower concen trations the electron-C-13 dipolar contribution to the line width domi nates and the width of the line remains constant. Since the pulse sequ ence employed for T-2 measurements eliminates the effects of inhomogen eous line broadening, T-2(-1) of the m(I) = 0 line remains linearly de pendent on the total paramagnetic impurity concentration, even at very low paramagnetic impurity concentrations.