Origin of ferromagnetism in nitrogen embedded ZnO : N thin films

Nitrogen embedded ZnO : N films prepared by pulsed laser deposition exhibit significant ferromagnetism. The presence of nitrogen ions contained in ZnO is confirmed by the secondary ion microscopic spectrum and by Raman experiments, and the embedded nitrogen ions can be regarded as defects. According to the experimental results, a mechanism is proposed based on one of the electrons in the completely filled d-orbits of Zn that compensates the dangling bonds of nitrogen ions and leads to a net spin of one-half in the Zn orbits. These one-half spins strongly correlate with localized electrons that are captured by defects to form ferromagnetism. Eventually, the magnetism of nitrogen embedded ZnO : N films could be described by a bound magnetic polaron model.