Neighborhood notion in the magnetic-properties study of magnetic materials with a dominant superexchange interaction

The steplike magnetization observed in a semimagnetic semiconductor in a high magnetic field allows an accurate determination of the exchange interaction of these compounds. Nevertheless, the results obtained from a generalized cluster model or extended nearest-neighbor pair approximation for an interaction longer than nearest neighbor do not agree well with experimental measurements (specific heat, spin-glass study, etc.). From the assumption of a preponderant superexchange, reconsidering the hypothesis of an exchange-constant decrease with the direct distance, we analyze the ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Te magnetization for different Mn compositions, and we obtain good agreement with experimental results. We emphasize that to study the magnetic properties of materials in which this interaction mechanism is preponderant, the neighborhood notion should be reconsidered, taking into consideration the cation-anion-cation distances and angles.