Defects localization and nature in bulk and thin film utrananocrystalline diamond

We report about the electron paramagnetic resonance and nuclear magnetic resonance signals in bulk and thin film-type ultrananocrystalline diamond with and without nitrogen. The localization and nature of defects for powder and compact film samples were analyzed. From the analysis of spin–lattice and spin–spin relaxation times, we have found that spin states sit in sp2 enriched region belonging to the grain boundaries.