Magnetic exchange coupling in (Dy,Tb)FeCo magneto-optical recording films

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