  We present a study of the damping and spin pumping properties of CoFeB/X/Pt
systems with $\rm X=Al,Cr$ and $\rm Ta$. We show that the total damping of the
CoFeB/Pt systems is strongly reduced when an interlayer is introduced
independently of the material. Using a model that considers spin relaxation, we
identify the origin of this contribution in the magnetically polarized Pt
formed by the magnetic proximity effect (MPE), which is suppressed by the
introduction of the interlayer. The induced ferromagnetic order in the Pt layer
is confirmed by transverse magneto-optical Kerr spectroscopy at the M$_{2,3}$
and N$_7$ absorption edges as an element-sensitive probe. We discuss the impact
of the MPE on parameter extraction in the spin transport model.
