Thickness Dependence of Magneto-Optic Effects in Tb-Fe Film

In the investigation of amorphous rare earth-transition metal (RE-TM) thin films for magneto-optic (M-O) storage applications, optimization of Kerr effect enhancement using dielectric overcoating in a bilayer structure has been the subject of numerous theoretical calculations [1]. It has been generally assumed that the optical constants such as the refractive index, absorption coefficient and dielectric tensor of the M-O film are independent of the film thickness. However, in light of a recent report which shows a strong thickness dependence of magnetic hysteretic properties and Curie temperature of the Tb-Fe films due to variation in the microstructure [2], it is necessary to investigate experimentally the optical enhancement of the Kerr effect in media having varying RE-TM film thickness and compare that to the theoretical results.