Spin-valve films using synthetic ferrimagnets for pinned layer

The magnetic behavior of spin-valve films using Co(t₁)/Ru(0.8 nm)/Co(t₂) synthetic ferrimagnets for the pinned layer were investigated, in which the Co(t₂) layer is exchange-biased by a CrMnPt antiferromagnetic layer. As compared with experimental results, the magnetic behavior of Co/Ru/Co/CrMnPt films could be qualitatively explained on the basis of a coherent rotation model and was roughly classified into two cases according to the thickness of t₁ and t₂. For t₁=t₂ the magnetization of the two Co layers changed the direction only in gentle rotation mode, which resulted in very large pinning fields. For t₁≠t₂ the direction of the magnetization of the two Co layers rapidly reversed, maintaining an antiparallel magnetic configuration, at a relatively small applied field. The field where 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 t₁-t₂