Antiferromagnetic superexchange interaction between Fe super(3+) ions in Fe super(3+) doped wide-gap oxide of beta -Ga sub(2-x)Fe sub(x)O sub(3) (x=0.1, 0.2, 0.3, 0.4)

In the Fe super(3+) doped wide-gap oxide of beta -Ga sub(2_x)Fe sub(x)O sub(3) (x=0.1, 0.2, 0.3, 0.4), Rietveld refinements of the X-ray diffraction data show that the Fe super(3+) ions are preferentially occupied on the octahedral sites. From the measurements of magnetization as a function of magnetic field and inverse molar susceptibility as a function of temperature, it is found that the superexchange interaction between Fe super(3+) ions via an intermediate oxygen ion is antiferromagnetic. The optical bandgap (E sub(g)) is found to decrease monotonically in energy upon increasing the Fe super(3+) concentration. Below the E sub(g) edge, optical absorption subspectra are observed to occur at ~1.8 and ~2.7 eV, which are attributed to the d-d transitions of the crystal-field splitting of 3d super(5) multiplets of the octahedral Fe super(3+) ion.