We have studied growth and magnetism of Fe on graphene and graphite surfaces grown on SiC substrate. Magneto-optical Kerr effect (MOKE) results show that the magnetic dead layer exists on both surfaces. Fe on graphene exhibits larger magnetic anisotropy with almost perfect remanence magnetization above Fe deposition of nominal 7.5 Å thickness. On the other hand, Fe on graphite, with oval nanoparticles, has a low magnetic anisotropy, and hysteresis appears at Fe deposition of nominal 15 Å thickness. X-ray photoelectron measurements suggest that the higher anisotropy and thinner magnetic dead layer for Fe/graphene does not come from the difference in interface mixing. A structural investigation by scanning tunneling microscopy reveals that Fe forms nanoparticles on both carbonized surfaces and that on graphene the aspect ratio of the Fe particles between the height and width is much smaller compared with that on graphite. The shape anisotropy originating from the morphological changes is consistent with the MOKE results. The formation of the low-profile Fe nanoparticle on the graphene indicates the higher surface energy on the graphene/SiC. The different surface energy derived from the interaction between graphene layer and the substrate drastically modifies magnetic properties of Fe overlayers.
All Science Journal Classification (ASJC) codes
- 化学 (全般)