Low temperature electron spin resonance investigation of ultrananocrystalline diamond films as a function of nitrogen content

We have investigated the room and low temperature ESR signals in a series of ultrananocrystalline diamond films grown with different N2 enrichments in the gas phase. We have found that exchange interaction is playing the major role in spin–spin interaction and determines the linewidths. The relatively high values of spin–lattice relaxation and other features of the ESR signals show that the ESR active centers are sitting in the grain boundaries' regions.