  Nitrogen embedded ZnO:N films prepared by pulsed laser deposition exhibit
significant ferromagnetism. The nitrogen ions contained in ZnO confirmed by
Secondary Ion Microscopic Spectrum and Raman experiments and the embedded
nitrogen ions can be regarded as defects. According to the experiment 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.
