Magneto-Optical Recording
Improvement of Magneto-Optic Properties by Multilayered Structure
1985 Volume 9 Issue 2 Pages 105-108
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1985 Volume 9 Issue 2 Pages 105-108
It has been found that the magneto-optic properties of rare earth-transition metal (RE-TM) amorphous thin films, which are used as magneto-optical memory media, can be enhanced by a multilayered structure using the interference of light.
The apparent refractive index of the substrate can be varied by coating the appropriate dielectric layer which has an optical thickness of 1/4 of the laser wavelength λ. By inserting this λ/4-layer between the substrate and the conventional dielectric layer for Kerr enhancement/RE-TM layer/reflector-structure, figure of merit √Rθk (θk: Kerr rotation, R: reflectivity) can be improved by 6∼7 dB for R≥0.1 compared to a simple substrate/RE-TM layer-structure.
This figure of merit is almost the same as the one previously reported for a substrate/RE-TM layer/dielectric layerlreflector-structure. However, since the thickness of the RE-TM layer of the former structure is larger than that of the latter, it is considered to be more suitable as a recording medium taking reliability into account.
