Composition and wavelength dependence of the Faraday rotation of amorphous gadolinium alloys

Measurements of the wavelength dependence of the Faraday rotation θ
F
for thin film amorphous ferrimagnetic alloys of Gd with Co, Fe or FeCo show values of θ
F
increasing up to 3×10
⁵
deg/cm with increasing wavelength. The data fits a model in which the contributions to θ
F
of the two ferrimagnetic subnetworks are independent of each other and are additive, It is found that the contribution of Gd to θ
F
is zero in Co-rich compositions.