Nano-Materials Design for High- T_C Ferromagnets of Ti_(1-x)Co_xO_2 Nanosheets

摘要

We present materials design of high- T_C ferromagnetic nanomaterials based on first-principles calculations. Two-dimensional (2D) titania nanosheet, a recently discovered room-temperature (RT) ferromagnetic nanomaterial, is an important target for 2D ferromagnets. In Ti_(1-x)Co_xO_2 nanosheets with Co~(2+) oxidation state, the ferromagnetic states are highly stabilized up to x= 0.5 with a modest doping dependence of magnetic moment (～1 μ_B/Co). Moreover, we find that tailoring properties could be achieved by tuning Co oxidation states, and the optimally doped Ti_(1-x)Co_xO_2 nanosheets (Co~(3+); x= 0.125, 0.25) are found to be an excellent RT half-metallic ferromagnet with a large magnetic moment (～4 μ_B/Co). 2D nanosheet is therefore expected to provide a very useful platform for nanoscale spinelectronics devices.