MAGNETOOPTICAL PROPERTIES OF FE-PT ALLOY-FILMS IN THE RANGE 1.55-10.5 EV

The optical and magneto-optical properties of as-deposited and annealed Fe51Pt49 films were investigated in the photon energy range 1.55-10.5 eV. The magneto-optical Kerr rotation (theta(K)) spectra of both films were found to show a dispersion-type structure in the 4.6-7.8 eV region: they have large negative and broad positive peaks at around 4.8 and 7.8 eV, respectively. The theta(K) spectra showed a tendency that is essentially quite similar to that of bulk Fe. The Kerr ellipticity (eta(K)) spectra are bell shaped, exhibiting a large negative peak at 6.3 eV. Plasma edges were observed at 6.9 eV for the as-deposited film and at 7.3 eV for the annealed film. The absolute value of the real part of the off-diagonal dielectric element (epsilon(XY)') of both films at approximately 4.8 eV are almost the same as that of bulk Fe. This leads to the conclusion that the theta(K) enhancement at 4.8 eV is mainly due to a decrease in epsilon(XX)'' and a peak shift in epsilon(XY)' towards lower energy, but not to a plasma-resonance effect.