The magnetic behavior of spin-valve films using Co(t(1))/Ru(0.8 nm)/Co(t(2)
) synthetic ferrimagnets for the pinned layer were investigated, in which t
he Co(t(2)) layer is exchange-biased by a CrMnPt antiferromagnetic layer. A
s compared with experimental results, the magnetic behavior of Co/Ru/Co/CrM
nPt films could be qualitatively explained on the basis of a coherent rotat
ion model and was roughly classified into two cases according to the thickn
ess of t(1) and t(2). For t(1) = t(2) the magnetization of the two Co layer
s changed the direction only in gentle rotation mode, which resulted in ver
y large pinning fields. For t(1) not equal t(2) the direction of the magnet
ization of the two Co layers rapidly reversed, maintaining an antiparallel
magnetic configuration, at a relatively small applied field. The field wher
e the rapid magnetization reversal was caused agreed with the exchange-bias
field in the spin-valve film with a single Co pinned layer whose thickness
was t(1) - t(2).