Charge-spin current conversion in high quality epitaxial Fe/Pt systems: Isotropic spin Hall angle along different in-plane crystalline directions

Abstract

We report the growth of MgO[001]//Fe(6 nm)/MgO(7 nm) and MgO[001]//Fe(6 nm)/Pt(6 nm) by molecular beam epitaxy and show that the full characterization by spin-orbit ferromagnetic resonance (SO-FMR) allows the determination of magnetic anisotropies by classical FMR-only studies. The spin mixing conductance of the epitaxial Fe/Pt interface was measured to be geffect↑↓=2.6±0.5×1019 m2, and the effective spin Hall angle (SHA) θSHEeffect was estimated at different in-plane crystalline directions. It was found that θSHEeffect is the same in all directions. When taking into account high enough excitation frequencies to achieve uniform precession of magnetization, the effective SHA for epitaxial Pt in Fe/Pt is θSHEeffect=0.051±0.005. We address about the proper conditions to determine those relevant spintronic parameters.