Paramagnetic Properties of Synthetic Diamond Crystals Obtained in Ni-Mn-C System with Iron Doping

Abstract

Diamond crystals were synthesized at 4.5GPa and 1300°C in a Ni-Mn-C system with and without Fe doping. The reactive mixture was prepared with 50 wt% graphite and 50 wt% Ni-Mn followed by doping of 2 to 5wt% of pure iron. The synthesis was performed inside an anvil type high pressure device. After extraction and purification, the paramagnetic properties of the diamond crystals were evaluated by specific techniques at room temperature. It was found that the diamond synthesized with different iron content exhibit different paramagnetic properties. The data obtained by infrared spectroscopy and electron spin resonance (ESR) spectroscopy are coincident for radiation defects and different for nitrogen centers. The spectra of the electron spin resonance exhibited broad lines produced by residual impurities of Fe compounds together with catalyst alloy and were accompanied by a distortion of the spectrum of paramagnetic nitrogen in the form of a tilt of the ESR spectra with respect to the zero line.