Nuclear magnetic relaxation studies of Ga-69, Ga-71, and As-75 nuclei in GaAs single crystals doped with paramagnetic impurities

Abstract

The GaAs, GaAs:In,Cr, and GaAs:Mn single crystals were grown by the vertical gradient freeze (VGF) technique. The spin-lattice relaxation processes of Ga-69, Ga-71 and As-75 have been studied for the undoped GaAs single crystals and crystals doped with paramagnetic impurities Cr and Mn. The relaxation processes in all samples are well described by a single exponential function. The T-2 dependence of the relaxation rate was in accordance with that predicted for the Raman mechanism of nuclear spin-lattice relaxation for all crystals investigated. The manganese doping showed a tendency to shorten slightly the spin-lattice relaxation times. (C) 1999 Elsevier Science Ltd. All rights reserved.