Computation of optical properties of multilayered media for magneto‐optical memories

摘要

Amorphous rare‐earth/transition metal alloys are efficient materials for high‐density magneto‐optical memory discs. To optimize the figure of merit F=R×sin2θ (R is the reflection coefficient and θ is the peak to peak Kerr rotation), the alloys are used as very thin films in multilayered structures. Kerr and Faraday effects combined with interference effects enhance F. A computation of numerous parameters (optical and magneto‐optical indices and thickness of each layer) is necessary to optimize this structure. The computation we propose is based on the recurrent Heavens’ method taking into account the circular birefringence of the magnetic layer, and leads to realistic values of F. The computation method is outlined in this paper and the agreement between experimental and theoretical results discussed for GdFe alloys.