The spin-fluctuation spectrum of an extended t-J model appropriate to
bilayer Y-Ba-Cu-0 is investigated within a renormalized-mean-field app
roach. Strong antiferromagnetic correlation between bilayers is found.
for realistic values of the interplane coupling in a regime where the
inplane susceptibility is strongly exchange enhanced even though the a
ntiferromagnetic correlation length is short. The influence of spin pa
iring on the spin-fluctuation spectrum, in this case via a d-wave orde
r parameter, is included. The model predicts a strong energy dependenc
e of the modulation in the vicinity of the characteristic energy for s
pin fluctuations.