“Flatlands” in Spintronics: Controlling Magnetism by Magnetic Proximity Effect

Abstract

Carbon atoms in graphene gain magnetic moments when in contact with magnetic substrates, following the macroscopic substrate alignment even at ambient temperature (Weser, M. et al.: Appl. Phys. Lett. 96, 012504 (2010)). On the other hand, magnetically doped topological insulators are ferromagnetic only at low temperatures (\(T_c=13\,\hbox{K}\) in \(\hbox{\it Bi}_{2-x}\hbox{\it Mn}_{x}\hbox{\it Te}_{3}\)) (Hor, Y.S. et al.: Phys. Rev. B 81(81), 195203 (2010)). Here we report chemical selective polarization dependent X-ray experiments on \(\hbox{{\it Fe}/{\it Bi}}_{2-x}\hbox{\it Mn}_{x}\hbox{\it Te}_{3}\) interfaces, where we followed the temperature dependence of the magnetic properties of Mn doped topological insulator in proximity with magnetic iron film. We find the presence of robust long range ferromagnetism in Mn induced by the magnetic proximity effect and maintained up to the room temperature (Vobornik, I. et al.: Nano. Lett. 11(10), 4079 (2011)). These results trace path to interface-controlled ferromagnetism in novel (graphene and topological insulators) “flatlands”.