Magnetic Characteristics of Carbon-Doped Nanocrystalline TiO 2

Carbon doped TiO sub(2) nanocrystal powder samples with various C contents were synthesized by a low-temperature sol-gel method, and a large lattice C contents of 12.7% was obtained. We demonstrated that the C ions were homogenously doped into the TiO sub(2) matrix at the form of substitutional C (Cs-o) and interstitial C (C sub(I)), without precipitation of TiC and other impurity phase. Our results show that C-doped TiO sub(2) is ferromagnetic with the Curie temperature well above room temperature. The magnetization is mainly related to the content of Cs-o, suggesting that the intrinsic ferromagnetism originates from the Ti-C system in the TiO sub(2) environment.