  We systematically measure and analyze the spin diffusion length and the spin
Hall effect in Pt with a wide range of conductivities using the spin absorption
method in lateral spin valve devices. We observe a linear relation between the
spin diffusion length and the conductivity, evidencing that the spin relaxation
in Pt is governed by the Elliott-Yafet mechanism. We find a single intrinsic
spin Hall conductivity ($\sigma_{SH}^{int}=1600\pm150\: \Omega^{-1}cm^{-1}$)
for Pt in the full range studied which is in good agreement with theory. For
the first time we have obtained the crossover between the moderately dirty and
the superclean scaling regimes of the spin Hall effect by tuning the
conductivity. This is equivalent to that obtained for the anomalous Hall
effect. Our results explain the spread of the spin Hall angle values in the
literature and find a route to maximize this important parameter.
