Magneto-optic Kerr effect of amorphous Gd-Fe films

The magneto-optic polar Kerr spectra (λ = 400 to 700 nm ) have been measured at 4.2 K for amorphous Gd-Fe, Gd-Cu, Gd-Ni and Y-Fe films. The spectra of Gd-Fe films are compared with those of amorphous films with single magnetlc component. It has been found that Gd-Cu and Gd-Ni films have Kerr spectra very different from crystalline Gd : The Kerr rotation θKis comparable to Gd at 400 nm while it becomes much smaller at 700 nm. The Kerr spectra of Gd-Fe films were found to agree qualitatively with the additive expression, θK= K(Fe).4πMs(Fe) + K(Gd).4πMs(Gd), where K(Fe) and K(Gd) are estimated from single magnetic component films. The results suggest that Gd contributes to the Kerr rotation in the short wavelength range.