Spin-lattice relaxation at high magnetic fields

Abstract

A new method of measuring the dynamics of magnetization at arbitrary magnetic field is presented. It is illustrated by measuring the spin-lattice relaxation rate in paramagnetic ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te in magnetic fields up to 25 T. At low fields, the spin-spin interaction of the Mn spins dominates the relaxation process; however, at high fields the relaxation of isolated spins can be observed. Among the spin clusters playing an important role as fast relaxation centers, exchange-coupled nearest-neighbor Mn pairs are identified, suggesting an important mixing of their states.