超高真空成膜によるPdPtMnスピンバルブ膜のMR特性  [in Japanese] MR Properties of PdPtMn Spin-Valve Films Fabricated by Ultrahigh-Vacuum Sputtering Process  [in Japanese]

We investigated the relation between the background pressure (P_<B.G.>) of the sputtering chamber and the unidirectional anisotropy field (Hua) of spin-valve films with PdPtMn antiferomagnetic layers fabricated by an ultrahigh vacuum (UHV) sputtering process. Hua increased with decreasing P_<B.G.> until P_<B.G.> reached 2 X 10^<-7> Pa. The UHV sputtering process helped to reduce the PdPtMn thickness from 25 nm, which was needed in the conventional high-vacuum (HV) sputtering process, to under 15 nm while preserving the magnitude of Hua. We fabricated a spin-valve structure with total thickness of 26.5 nm exhibiting a large MR ratio over 8.0%, sufficient Hua (>500 Oe), and large sheet resistance change (Δρ/t_<total<=1.6Ω)