Giant magnetic moments in ferromagnetic oxide semiconductors

Concentration dependence of the specific magnetic moment of Co-and Fe-doped titanium oxide semiconductors has been studied at room temperature. A sharp increase in the magnetic moment has been found at low concentrations of a magnetic impurity. A giant value of 22.9 μ_B per impurity atom has been detected in TiO₂ with a Co concentration of 0.15 at %, which has never been observed in oxide systems. The giant magnetic moments observed at low impurity concentration are attributed to the polarization of a crystal lattice. Comparison with the literature data indicates that the concentration dependences of magnetization are different in different oxide matrices.