High-resolution electron microscopy study of Ni81Fe19 film with Co33Cr67 buffer layer

The anisotropic magnetoresistance (AMR) in permalloy Ni81Fe19 film deposited on a 1.2nm Co33Cr67 buffer layer was significantly enhanced. The high-resolution electron microscopy was used to study the microstructure of Ni81Fe19 film with and without Co33Cr67 buffer layer. It was found that Co33Cr67 buffer layer can induce good (111) texture, while without Co33Cr67 buffer layer, Ni81Fe19 film show randomly oriented grain structure. The Δρ/ρ enhancement is attributed to the decrease in the resistivity ρ of the Ni81Fe19 film due to the formation of the large (111) textured grains in Ni81Fe19 film with Co33Cr67 buffer layer. However, the surface roughness of substrate may limit the (111) textured grain size and induce additional grain boundaries in Ni81Fe19 film with Co33Cr67 buffer layer, limit the enhancement of the AMR effect.