  Exploration of spin-currents in organic semiconductors (OSECs) induced by
resonant microwave absorption in ferromagnetic substrates has been of great
interest for potential spintronics applications. Due to the inherently weak
spin-orbit coupling (SOC) of OSECs, their inverse spin Hall effect (ISHE)
response is very subtle; limited by the microwave power applicable under
continuous-wave (cw) excitation. Here we introduce a novel approach for
generating significant ISHE signals using pulsed ferromagnetic resonance, where
the ISHE is ~2-3 orders of magnitude larger compared to cw excitation. This
strong ISHE enables us to investigate a variety of OSECs ranging from
pi-conjugated polymers with strong SOC that contain intrachain platinum atoms,
to weak SOC polymers, to C60 films, where the SOC is predominantly caused by
the molecule surface curvature. The pulsed-ISHE technique offers a robust route
for efficient injection and detection schemes of spin-currents at room
temperature, and paves the way for spin-orbitronics in plastic materials.
