Composition and wavelength dependence of the faraday rotation of amorphous gadoltnium alloys

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