Magneto-Optical Properties of TbFeCo Amorphous Films with Al Reflector

The TbFeCo thin films with dense, uniform and columnless microstructure have been prepared as magneto-optical(MO) recording media by using facing targets type of sputtering(FTS) apparatus. The Kerr rotation angle θk and the reflectivity R of TbFeCo(MO) layers with and without Al reflective layer were measured for the light wavelength λ in the range of 450–850 nm and the MO layer thickness tMO in the range of 30–150 nm. θk of the double layers type of TbFeCo/Al fms took maximum of 0.54 deg.(λ =830 nm) at tMO of about 40 nm. Furthermore, θk and R of the double layers type of films for various tMO were theoretically calculated, based on the already known optical constants of TbFe, Al and /or TbOx. Though they were qualitatively in agreement with the experimental data, there was a large discrepancy between the estimated values and the experimental results. This may be attributed to the uncertainty of available optical constants such as refractive indicies and dielectric tensors quoted in this calculation.