Influence of synthesis conditions and of neutron irradiation on physical properties of spontaneous crystalline diamonds

The influence of fine crystalline diamond powder synthesis conditions and their further irradiation by the neutrons of fission spectrum on the processes of natural and impurity defect (AlN) formation has been investigated. Non-monotonous change of paramagnetic nickel-containing defect concentration has been determined as being dependent both on the synthesis duration and on the influence of neutron irradiation. It is shown that the behavior of impurities in crystals depends on the processes occurring during their synthesis. Some similar changes of the paramagnetic nickel concentration under the influence of various factors (time, size and radiation) have been established. It has also been determined that the change in defects with g = 2.003 concentration is due to the change of the lattice point nitrogen defect concentration. The obtained results may be used to determine the conditions of spontaneous diamond crystallization in a closed system under high pressures and temperatures.