The Effect of Injection Layers on a Room Temperature Organic Spin Valve

Organic spin-valve devices with tris 8-hydroxyquinoline aluminium (Alq₃) as a spacer layer and Fe₅₀Co₅₀ and Ni₈₁Fe₁₉ as the spin-polarized ferromagnetic electrodes have been fabricated. Additional organic layers of N, N´-diphenyl-N, N´ bis(3-methylphenyl)-(1, 1´-biphenyl)-4, 4´ diamine (TPD) and LiF were added to study the changes in the spin injection and extraction efficiency of the carriers into and from the organic spacer layer. Room temperature magnetoresistance (MR) measurements were carried out. The MR was observed to be the largest in the devices containing both additional layers, indicating the crucial role of injection and collection efficiency at the interfaces in the degree of spin-polarized conduction in these structures.