Defect related room temperature ferromagnetism in N-implanted ZnO film

抄録

Ion implantation was used to introduce N-ions into a ZnO film, which was deposited on sapphire by pulsed-laser deposition. The implantation fluence of N-ions was about 5 × 10¹⁶ cm⁻². The annealing behavior of ferromagnetism and structures of the N-implanted ZnO sample were determined by a vibrating sample magnetometer and X-ray diffraction, respectively. Positron annihilation spectroscopy and Raman spectroscopy were also employed to investigate the defect conditions in the sample. We observed that room temperature ferromagnetism can be introduced by V_Zn-related defect-complexes instead of only by substitutional N-ions. The results were supported by ab initio calculations based on density functional theory. Also, the possibility of oxygen vacancies as the origin of the ferromagnetism was clearly ruled out.