Ferromagnetism in two-dimensionalTi0.8Co0.2O2nanosheets

We have investigated magnetic and magneto-optical properties of two-dimensional (2D) ${\mathrm{Ti}}_{0.8}{\mathrm{Co}}_{0.2}{\mathrm{O}}_{2}$ 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 ${\mathrm{Ti}}_{0.8}{\mathrm{Co}}_{0.2}{\mathrm{O}}_{2}$ nanosheets exhibit room-temperature ferromagnetism with magnetic moment of $1.4{\ensuremath{\mu}}_{B}∕\mathrm{Co}$. We also observe robust magnetic circular dichroism near the absorption edge at $4\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, indicating a strong spin polarization in this 2D system. The first-principles study of ${\mathrm{Ti}}_{0.8}{\mathrm{Co}}_{0.2}{\mathrm{O}}_{2}$ nanosheet characterizes the ferromagnetic state with a spin-orbit-induced anisotropy.