Technical saturation and magnetization steps in diluted magnetic semiconductors: Predictions and observations

Abstract

A model for the high-field magnetization of II-VI semimagnetic compound semiconductors at low temperatures is presented. It applies for low Mn concentrations. The model explains quantitatively and without adjustable parameters the magnetization of ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Te}$, ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$, ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{S}$, ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$, and ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{S}$ near 100 kOe for $T<2$ K. At higher magnetic fields, magnetization steps are predicted. The first step is observed in ${\mathrm{Cd}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$ and ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$, and is used to determine the nearest-neighbor exchange constant. The results support a random distribution of Mn ions.