  An electric current flowing in Pt, a material with strong spin-orbit
coupling, leads to spins accumulating at the interfaces by virtue of the spin
Hall effect and interfacial charge-spin conversion. We measure the influence of
these interfacial magnetic moments onto adjacent 3d transition metal layers by
x-ray absorption spectroscopy and x-ray magnetic circular dichroism in a
quantitative and element-selective way, with sensitivity below $10^{-5}~\mu_B$
per atom. In Pt(6 nm)/Co(2.5 nm), the accumulated spins cause a deviation of
the Co magnetization direction, which corresponds to an effective spin-Hall
angle of 0.08. The spin and orbital magnetic moments of Co are affected in
equal proportion by the absorption of the spin current, showing that the
transfer of orbital momentum from the recently predicted orbital Hall effect is
either below our detection limit, or not directed to the 3d states of Co. For
Pt/NM (NM = Ti, Cr, Cu), we find upper limits for the amount of injected spins
corresponding to about $3\times 10^{-6}~\mu_B$ per atom.
