Revealing the importance of interfaces for pure spin current transport

Spin transport phenomena underpin an extensive range of spintronic eects. In particular spin transport across interfaces occurs in most device concepts; but is so far poorly understood. As interface properties strongly impact spin transport, one needs to characterize and correlate them to the fabrication method. Here we investigate pure spin current transport across interfaces and connect this with imaging of the interfaces. We study the detection of pure spin currents via the inverse spin Hall eect in Pt and the related spin current absorption by Pt in Py-Cu-Pt lateral spin valves. Depending on the fabrication process to pattern the Cu bridge, we either determine a large (inverse) spin Hall eect signal and low spin absorption by Pt or vice versa. We explain these counter-intuitive results by the fabrication induced varying quality of the Cu/Pt interfaces, which is directly revealed via a special scanning electron microscopy technique for buried interface imaging.