Nuclear spin-lattice relaxation of dilute spins in semiconducting diamond

Abstract

Absorption line shape and spin-lattice relaxation-time measurements have been made on $^{13}\mathrm{C}$ nuclei (1.1% abundant) in a type-IIb single-crystal semiconducting diamond. The line shape measurements are consistent with theoretical predictions for a dilute spin system. Over the temperature range 295--375 K, the spin-lattice relaxation time is long (3--4 h) and shows a temperature dependence which may be explained by means of a model in which spin diffusion plays a role, and the paramagnetic acceptor centers relax via an Orbach-type process involving excited states near the valence band.