Properties of spin-valve structures deposited on step-bunched vicinal surfaces

We have investigated the properties of Co/Cu/FeNi spin-valve structures deposited on step-bunched vicinal Si(1 1 1) substrates. We first discuss the in-plane uniaxial magnetic anisotropy induced in each magnetic layer by the initial surface corrugation. A ferromagnetic coupling of the two magnetizations is found, which is analyzed as a function of the spacer-layer thickness. Giant magnetoresistance (GMR) of the spin-valve structures is then investigated as a function of the in-plane current direction. Because of the initial corrugation, we observe current perpendicular to the plane (CPP) contributions to the GMR of the spin-valve structures. These CPP contributions can lead to an increase of the absolute GMR by up to 70% at room temperature, when the current is applied perpendicular to the steps direction.