  We present a density functional study of Fe doped into the tetrahedral and
octahedral cation sites of the wide band gap spinel ZnGa$_2$O$_4$.
  We calculate the electronic structure for different substitutions and discuss
the magnetic and transport properties for each case considering different
approximations for the exchange-correlation potential. We show that for certain
doped cases, significant differences in the predicted behavior are obtained
depending on the exchange correlation potential adopted. Possible applications
of the doped systems as magnetic semiconductors are outlined.
