Elucidation of the strong effect of an interfacial monolayer on magnetoresistance in giant magnetoresistive devices with current perpendicular to the plane

Electronic band matching at the heterointerface between magnetic and nonmagnetic metals influences spin-dependent transport through that interface. However, the impact of atomic-level interfacial structure on the electronic band matching and the resultant transport properties have not been clarified. Here, the authors have fabricated high-quality epitaxial giant magnetoresistance devices with half-metallic Heusler electrodes with interfacial ultrathin Ni insertion layers. Through state-of-the-art microstructure analysis, they demonstrate that even a monolayer of Ni strongly affects interfacial band matching and giant magnetoresistance.