Ferromagnetism in two-dimensional Ti0.8Co0.2O2 nanosheets

We have investigated magnetic and magneto-optical properties of two-dimensional (2D) Ti0.8Co0.2O2 nanosheet, a new nanosized titanium oxide derived from layered titanates by exfoliation. Despite heavy doped 2D system in the dielectric ground, the multilayer films of Ti0.8Co0.2O2 nanosheets exhibit room-temperature ferromagnetism with magnetic moment of 1.4 mu(B)/Co. We also observe robust magnetic circular dichroism near the absorption edge at 4 eV, indicating a strong spin polarization in this 2D system. The first-principles study of Ti0.8Co0.2O2 nanosheet characterizes the ferromagnetic state with a spin-orbit-induced anisotropy.