  Ferromagnetic/antiferromagnetic bilayers are interfaced with normal
metal/ferromagnetic bilayers to form F*/AF/N/F valves. The N-spacer thickness
is chosen such that it mediates strong indirect exchange (RKKY) between the
outer magnetic layers, which varies in strength/direction depending on the N
thickness and in direction on switching F. The system exhibits a strong
modulation of the F*/AF exchange bias, oscillating in strength syncronously
with the oscillation in the interlayer RKKY exchange across the normal metal
spacer. The effect is explained as due to a superposition taking place within
the antiferromagnetic layer of the direct-exchange proximity effect from the
F*/AF interface and the indirect RKKY exchange from F penetrating AF via N. The
modulation, expressed via the strength of the F*/AF bias field, reaches 400% at
the first RKKY peak.
