Enhanced Exchange Bias of Spin Valves Fabricated on Fullerene-Based Seed Layers

The magnetic properties of exchange biased systems deposited on top of fullerene-based materials have been studied. An enhanced exchange bias field has been observed for Si/SiO
₂
/C
₆₀
/Co/Cu/Co/IrMn/Ta and Si/SiO
₂
/FeC
₆₀
/Co/Cu/Co/IrMn/Ta in comparison to a typical structure of Si/SiO
₂
/Ta/Co/Cu/Co/IrMn/Ta. Here the magnetic properties of the devices are changed significantly with an organic underlayer or seed layer. The magnetic ordering is well maintained, and C
₆₀
seeding results in an exchange bias of (19.5 ±0.5) mT, some 7 mT higher than that of Ta seeded spin valves (12.5 ±0.5 mT). A combination of MOKE (magneto-optical Kerr effect), X-ray diffraction and Raman spectroscopy have been used to characterize the materials and further understand the interactions between the Co and fullerene-based materials.