Influence of phase structural transformations on optical and magnetooptical characteristics of Fe-Ni alloys

Frequency dependences of optical and magnetooptical characteristics of Fe1-xNix alloys (0.42≤x≤0.69) in different phases (amorphous, crystal, ordered, equilibrium) are studied. The diagonal and nondiagonal components of the permittivity tensor are calculated. Changes in the spectra due to order-disorder transformation, and transformation from amorphous phase into crystal phase are observed. Formation of an ordered phase according to the L10 type is detected. Peculiarities of the spectral behaviour of the ordered phase are explained by the occurrence of antiferromagnetic interaction of iron atoms and formation of Fe impurity level in the subzone with the spin ↑