Model cluster calculations by discrete variational-X alpha method for the Fe3+ ions at 8b and 24d sites of the In2O3 crystal lattice demonstrated that the density of states of the Fe3+ 3d electrons located around the center of the band gap, and the spin density of states for the Fe3+ ions at 8b and 24d sites are asymmetric. For Fe-doped In2O3 powders, we found a cusp at approximate to 30 K overlapping cluster glass behavior in dc susceptibility, though the Cusp showed no frequency dependence in ac susceptibility. The cusp at approximate to 30 K for the Fe-doped In2O3 powders can be attributed to superexchange interactions between Fe3+ ions substituted for In3+ ions of the In2O3 crystal lattice. (c) 2005 Elsevier B.V All rights reserved.