Polycrystalline CPP-GMR Pseudospin Valves Using <inline-formula> <tex-math notation="LaTeX">$\langle {001}\rangle $ </tex-math></inline-formula> Textured Co<sub>2</sub>Fe(Ga<sub>0.5</sub>Ge<sub>0.5</sub>) Layer Grown on a Conductive (Mg<sub>0.5</sub>Ti<sub>0.5</sub>)O Buffer Layer

Abstract

We report the magnetotransport properties and the microstructure of polycrystalline current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) pseudospin valves (PSVs) using $\langle 001\rangle $ textured Co2Fe(Ga0.5Ge0.5) (CFGG) ferromagnetic layers grown on a conductive (Mg0.5Ti0.5)O (MTO) buffer layer. The PSV with a 10 nm CFGG on 2 nm MTO buffer layers annealed at 400 °C shows a resistance change–area ( $\Delta RA$ ) product of 6.6 $\text{m}\Omega ~\mu \text{m}^{2}$ . Interfacial roughness of the PSV multilayer has been substantially reduced (0.2 nm) compared with those of our previously reported MgO-buffered CFGG/Ag/CFGG PSVs. A relatively large magnetoresistance output and favorable interfacial smoothness make MTO a promising choice to fabricate a $\langle 001\rangle $ textured Heusler-alloy-based CPP-GMR device.