Effects of Fe substitution on the electronic, transport, and magnetic   properties of ZnGa$_2$O$_4$: A systematic ab-initio study
  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. 
Leonardo Pisani, Tulika Maitra, Roser Valenti