SPECTROSCOPY OF MULTILAYERS FOR MAGNETOOPTIC STORAGE

Ion beam sputtered TM/Co multilayers (TM = Au, Pd, Pt) with constant Co layer thickness d(Co) almost-equal-to 1.0 nm and transition metal thickness d(TM) = 0-8 nm have been investigated using optical and magneto-optical spectroscopy. The Au/Co spectra are dominated by optical constants effects in the vicinity of the plasma edge of Au (E(ph) almost-equal-to 2.4 eV). In contrast Pd and Pt containing multilayers show extra contributions to the magneto-optical activity sigma-approximately xy in the uv spectral region due to polarized 4d and 5d electronic excitations, respectively. Sigma-approximately xy (0.5 eV less-than-or-equal-to E(ph) less-than-or-equal-to 5.5 eV) data obtained at liquid helium temperature of high Pd and Pt content alloy films together with room-temperature data of pure Co are used to quantitatively simulate the measured spectra using a four layer model with magnetic Co, exchange polarized Pd or Pt on both sides, and non-magnetic Pd or Pt. The multiple reflection calculations are based on Fresnel's equations and account for all optical boundaries involved. They yield (exchange) induced polarization lengths of 0.80-0.90 nm for Pd layers in contact with almost-equal-to 1 nm Co layers. The magneto-optical effects in Pt/Co multilayers are governed by interface allow formation on a scale of 0.4-0.5 nm Pt corresponding to a Pt50Co50 composition.