Two-dimensional (2D) Ti1-xCoxO2 nanosheet, a recently discovered ferromagnic nanomaterial, has
been investigated by magnetic and magneto-optical measurements. The multilayer films of
Ti0.8Co0.2O2 nanosheets exhibit room-temperature ferromagnetism with magnetic moment of 1.4
μ 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 Ti1-xCoxO2
nanosheet characterizes the ferromagnetic state with a spin-orbit-induced anisotropy.