Results of research into the degradation of the magnetic and magnetooptical
properties of thin amorphous TbDyFeCo films under thermal annealing are pr
esented. The influence of the composition and parameters of protective over
layers on the corrosion resistance of amorphous films is studied. The prese
nce of two specific regions in the dependence of these parameters on the an
nealing time is established; moreover, in the initial region, these depende
nces obey the law In(t(ann)).