Ferromagnetic Property of Co and Ni Doped TiO2 Nanoparticles

The Co and Ni doped diluted magnetic semiconductor nanoparticle TiO2 is prepared by sol‐gel method. Ti0.97Co0.03O2, Ti0.97Ni0.03O2, Ti0.97Co0.06O2, and Ti0.97Ni0.06O2 samples were characterized by X‐ray scattering techniques and high resolution transmission electron microscope. The results show that there are no other phases existing in TiO2. As to the sample of high‐concentration dopant, the X‐ray scattering techniques have explored the existing of CoTiO3 and NiTiO3. The ferromagnetic measurement shows that the magnetization of the sample of high‐concentration dopant increases in the same external magnetic field. However, the relatively higher dopant Co and Ni may form more interstitial ions and paramagnet matters, reducing the oxygen vacancy concentration and finally leading to the decrease of remanent magnetization and coercivity of the materials.