Organic spin-valves based on fullerene C60*

Recent work suggests that the spin-transport length in organic semiconductors is limited by hyperfine coupling. Therefore, to potentially overcome this limitation, we fabricated spin-valves based on C60 for which the hyperfine coupling is minute. However, our devices do not show a significantly larger spin-diffusion length. This suggests that either a mechanism other than hyperfine coupling causes the loss of spin-polarization, or that in thick devices an increasing conductivity mismatch limits spin-injection.