Large enhancement of planar Hall sensitivity in NiO/NiFe/NiO heterostructure by interfacial modification

This paper reports a large enhancement of planar Hall sensitivity in Ta/NiFe/Ta films by intercalating NiO layers to Ta/NiFe and NiFe/Ta interfaces. The great improvement of the sensitivity derives from the increase of resistivity change (Δρ) and the decrease of saturation field (Hs). The enhancement of Δρ could be attributed to the strengthened spin dependent elastic scattering to the interfacial conductive electrons due to flat oxide/metal interfaces. Meanwhile, the existence of oxide (NiO) prevents the atomic interdiffusion of Ta and NiFe at the interfaces, which leads to the easier magnetization rotation of NiFe layer, resulting in lower saturation field.