Faraday rotation experiments in pulsed magnetic fields to 60 T were used to determine the nearest-neighbor d-d exchange interaction constant ${\mathit{J}}_1$ for Co in ${\mathrm{Cd}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Co}}_{\mathit{x}}$S. A single broad step is observed in the magnetization at ${\mathit{B}}_1$=41 T. After correcting for single-ion anisotropy and further-neighbor exchange fields, a value of ${\mathit{J}}_1$/${\mathit{k}}_{\mathit{B}}$=-30.3±1.5 K is obtained for the average exchange constant.

• Received 17 February 1995

DOI:https://doi.org/10.1103/PhysRevB.51.17561