  We have studied the evolution of the Spin Hall Effect in the regime where the
material size responsible for the spin accumulation is either smaller or larger
than the spin diffusion length. Lateral spin valve structures with Pt
insertions were successfully used to measure the spin absorption efficiency as
well as the spin accumulation in Pt induced through the spin Hall effect. Under
a constant applied current the results show a decrease of the spin accumulation
signal is more pronounced as the Pt thickness exceeds the spin diffusion
length. This implies that the spin accumulation originates from bulk scattering
inside the Pt wire and the spin diffusion length limits the SHE. We have also
analyzed the temperature variation of the spin hall conductivity to identify
the dominant scattering mechanism.
