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 as by classical FMR-only studies. The spin mixing conductance of epitaxial Fe/Pt interface was measured to be (1.5 +- 0.5)x10^19 m^2, and the effective spin Hall angle (SHA), was estimated at different in-plane crystalline directions. It was found that SHA is the same in all directions. When taking into account high enough excitation frequencies to achieve uniform precession of magnetization, the effective spin hall angle for epitaxial Pt in Fe/Pt is 0.051 +- 0.005. We address about the proper conditions to determine those relevant spintronics parameters.