Spectroscopic magneto-optic (MO) Kerr rotation experiments have been perfor
med on Pt/Co interfaces. This very sensitive experimental technique allows
a precise chemical analysis of this interface. From these measurements, we
deduced that the Co/Pt interface is formed of a disordered CoPt alloy layer
and a spin polarized platinum atomic monolayer whose MO indices were calcu
lated. In situ spectroscopic MO experiments have been performed during the
Pt growth on the hcp Co (0001) layer. In situ postdeposition annealing were
done on Pt/Co/Pt trilayers. In the 400-500 degrees C temperature range, th
e MO spectra show an important increase of the Kerr rotation, in particular
around 370 nm, while the magnetic anisotropy goes through a maximum at 500
degrees C. These results are related to the formation of a CoPt alloy orde
red along the (111) direction. (C) 1999 American Institute of Physics. [S00
21-8979(99)03313-7].