Exchange coupled magneto-optic layers

It is shown that it is possible to separate the storage function from the readout function by exchange coupling two layers, one with high magnetooptical rotation (readout layer) and the other with the coercivity and other properties necessary for small stable bits (storage layer). An investigation is described of the extent of coupling between a storage layer of Nd/sub 10/Tb/sub 20/ (FeCo)/sub 70/ with H/sub c/=5.4 kG and theta /sub K/=17 min and several readout layer compositions with H/sub c/>