The magnetic multilayers consisting of 3d-transition metal and noble metal(Pt or Pd) layers have attracted a lot of interest as a future magneto-optical storage medium for blue spectral region with increased information density. Compositionally modulated Ni/Pt multilayers were prepared at the Ar sputtering pressure of 7 mTorr by dc-magnetron sputtering method onto glass substrates. Recently, it was discovered that they have PMA(perpendicular magnetic anisotropy) at room temperature in our group. Magneto optical effect is related with the off-diagonal dielectric tensor element. So the ultimate object of this thesis is the determination of the dielectric tensor elements of Ni/Pt multilayers. We investigated the magneto-optical properties, namely, Kerr hysteresis loop, Kerr rotation and Kerr ellipticity with a homemade MOKES(Magneto-Optical Kerr and Ellipsometric Spectrometer) using photoelastic modulator. Kerr hysteresis loop was measured at the wavelength of 6000 Å with a maximum applied magnetic field of ±5kOe. These samples showed almost about 100% remanence, and Kerr rotation was about $0.1^*$. There were trends that Kerr rotation angles increased as the ratio of the thickness of Ni sublayer for a constant Pt layer thickness increased. We also presented the results of pure Ni for comparison. The spectra of Kerr rotation and ellipticity are measured at photon energies from 2 to 5 eV. After measuring the optical constant at the same photon energy range, we could determine the off-diagonal dielectric tensor element using the experimental data of Kerr rotation and ellipticity. We tried to interpret the off-diagonal dielectric tensor element in connection with electronic structure and the diagonal dielectric tensor element.
