DyFeCo films were d.c, sputtered from a magnetically unbalanced magnet
ron cathode. Their density, composition and magnetic properties were i
nvestigated systematically as a function of the sputter parameters pre
ssure and power, and were compared with evaporated films. They exhibit
a lower anisotropy constant and behave in terms of the ferrimagnetic
properties like evaporated films with 5 at.% less transition metal con
tent. Corresponding magneto-optical discs show a low recording perform
ance. These effects are attributed to the bombardment of the growing l
ayer with energetic particles during deposition, which probably leads
to a precipitation of transition metal clusters in the amorphous matri
x, possibly nanoscale superparamagnetic transition metal crystallites.