Absence of Significant Spin-Current Generation in Ti/Fe−Co−B Bilayers with Strong Interfacial Spin-Orbit Coupling

After one decade of the intensive theoretical and experimental explorations,\nwhether interfacial spin-orbit coupling (ISOC) at metallic magnetic interfaces\ncan effectively generate a spin current has remained in dispute. Here,\nutilizing the Ti/FeCoB bilayers that are unique for the negligible bulk spin\nHall effect and the strong tunable ISOC, we establish that there is no\nsignificant charge-to-spin conversion at magnetic interfaces via spin-orbit\nfiltering effect or Rashba-Edelstein(-like) effect even when the ISOC is\nstronger than that of a typical Pt/ferromagnet interface and can promote strong\nperpendicular magnetic anisotropy. We also find a minimal orbital Hall effect\nin 3d Ti.\n