Nano‐Materials Design for High‐ T C Ferromagnets of Ti 1‐x Co x O 2 Nanosheets

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 x O 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 x O 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.