Long-range ferromagnetic ordering at room temperature in Co+implanted TiO2nanorods

Long-range ferromagnetic ordering at room temperature is reported for post-annealed TiO2 nanorods doped with Co2+ by an ion implantation technique. The catalyst free anatase TiO2 nanorods are grown normal to the substrate plane. A Curie temperature of ~320?K was recorded for a ~9?at.% Co doped sample. Electronic structural studies confirm the substitutional Co in the Ti lattice site. Microstructural studies show the presence of extended defects, where a minor nonuniformity in doping concentration helps to sustain the intrinsic ferromagnetic ordering in Co doped TiO2 at room temperature. The projected nanorod tip size is found to be smaller than a single magnetic domain, which may lead to an increased signal-to-noise ratio for magnetic recording.