MAGNETIC EXCHANGE COUPLING IN (DY,TB)FECO MAGNETOOPTICAL RECORDING FILMS

The required bias field of a sperimagnetic film is governed by a finit e exchange coupling coefficient (lambda) mainly determined by the subn etwork coupling. From the study of a series of (Dy,Tb)FeCo films at co mpensation composition it is found that lambda is mainly determined by the concentration of the rare earth components. Moreover, the exchang e integral between rare earth and transition metal subnetworks can be derived from lambda so that the number of uncertain parameters for mea n held modeling is reduced. Accordingly, the bias field required for m agneto-optical recording is mainly proportional to lambda that can be obtained quantitatively from either measurement and/or mean field mode ling. (C) 1997 American Institute of Physics.