Room-temperature ferromagnetism in Cu-doped ZnO nanorods prepared using a microwave irradiation method

We report the observation of room-temperature ferromagnetism in Cu-doped ZnO nanorods prepared by using a microwave irradiation technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that Cu-doped ZnO had a single-phase nature with a wurtzite structure and that Cu ions had been successfully incorporated into the lattice positions of Zn ions in the ZnO matrix. Field-emission scanning electron microscopy (FESEM) and TEM micrographs suggested that the sizes of the Cu-doped ZnO nanorods ranges from 50 to 70 nm in diameter and 300 to 400 nm in length. The selected-area electron-diffraction (SAED) pattern indicated that the Cu-ZnO nanorods had a single-phase nature with a preferential growth direction along the [0 0 1] plane. Raman scattering spectra of Cu-doped ZnO nanorods revealed a blue shift of the E2 (high) mode that was related to the vibration of oxygen atoms in wurtzite ZnO, suggesting successful doping of Cu at the Zn site in ZnO. Magnetization measurements showed that the nanorods exhibited room-temperature ferromagnetism.