A magnetooptic layer made from rare-earth metals and transition metals exhibits a gradient in the alloy composition over the layer depth, and has a coercive field strength of more than 8 kOe in the temperature range of .DELTA.T=100.degree. C. around the compensation temperature T.sub.comp. The layer is fabricated with a dynamic sputter process, in which the substrates to be coated are led past one or a plurality of sputter targets, arranged in a common plane parallel to the track of the substrates. A mask is located between the sputter targets and the substrates.