Room-temperature ferromagnetism of diamagnetically-doped ZnO aligned nanorods fabricated by vapor reaction

Large-scale monocrystalline oxide-diluted magnetic semiconductor (ODMS) Zn_1−x Bi _x O nanorods arrays (NAs) were prepared within a large doping concentration range from 5% to 20% by a simple chemical vapor deposition. X-ray diffraction and high-resolution transmission electron microscopy reveal the monotonous expansion of the lattice constants with increasing Bi content, due to the effective Bi doping. In particular, room-temperature ferromagnetic (RTFM) behavior with Curie temperature over 363.7 K has been observed based on Bi-doped ZnO nanoarrays, whereas undoped ZnO NAs disappear. The RTFM origin is suggested, in which vacancies can be controlled to tune the FM. The as-formed RTFM NAs would have potential applications in many areas of advanced nanotechnology, such as new spintronic devices and magneto-optic components.