Spin Interactions in Cd_1-xMn_xS Bulk Crystals

Electron paramagnetic resonance (EPR) linewidth in the Cd1-xMnxS bulk crystals with manganese concentrations x = 0.25, 0.33, 0.35 and 0.42 has been studied in the high-temperature region. An analysis of the infinite-temperature EPR linewidth performed within the exchange narrowing model shows that the contributions of the anisotropic superexchange and magnetic dipolar interaction to the linewidth are nearly the same due to weak anion spin-orbit coupling. The single-ion anisotropy originating from the crystal field of axial symmetry with the parameter Dsingle= 0.0295 cm-1, as observed in some CdS:Mn crystals, gives a contribution to the linewidth comparable with the influence of the anisotropic superexchange and magnetic dipolar interaction. The calculated infinite-temperature linewidths, including all anisotropic spin interactions examined in this work, are close to the experimental infinite-temperature linewidths estimated from the existing high-temperature data.