Defect clusters in Fe1-xO and their ferrimagnetic properties

Ferrimagnetic properties, large saturation magnetization (M-s) and low temperature coercivity (H-c) was observed in nonstoichiometric Fe1-xO films. This unusual behavior was attributed to the existence of spinel type defect clusters coherently embedded in the FeO matrix. A model, which explains the Fe1-xO properties and predicts a linear dependence between M-s and the Fe1-xO lattice parameter a with the Fe3O4 data falling on the same line, is proposed. The experimental M-s vs a curve is in excellent agreement with the theoretical prediction, which indicates the existence of a fundamental relation between FeO, Fe1-xO, and Fe3O4. (C) 2000 American Institute of Physics. [S0021- 8979(00)47708-X].