  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.
