Magnetic susceptibility of diluted magnetic (semimagnetic) semiconductors: Further evidence for superexchange

We analyze the high-temperature magnetic-susceptibility data for ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$Se, together with new results for the quaternary systems ${\mathrm{Hg}}_{1\mathrm{-}\mathrm{x}\mathrm{-}\mathrm{y}}$ ${\mathrm{Mn}}_{\mathrm{x}}$ ${\mathrm{Cd}}_{\mathrm{y}}$Te and ${\mathrm{Hg}}_{1\mathrm{-}\mathrm{x}\mathrm{-}\mathrm{y}}$ ${\mathrm{Mn}}_{\mathrm{x}}$ ${\mathrm{Zn}}_{\mathrm{y}}$Te. This analysis provides unambiguous new evidence that superexchange interaction via anions (Te,Se) is the dominant mechanism of d-d coupling in $A_{1\mathrm{-}x}^{\mathrm{II}}$ ${\mathrm{Mn}}_{\mathrm{x}}$ ${\mathrm{B}}^{\mathrm{VI}}$ alloys. We also discuss briefly the relationship between the high- and low-temperature magnetic properties of these systems.