Room temperature ferromagnetism in carbon-implanted ZnO

Unexpected ferromagnetism has been observed in carbon doped ZnO films grown by pulsed laser deposition [H. Pan et al., Phys. Rev. Lett. 99, 127201 (2007)]. In this letter, we introduce carbon into ZnO films by ion implantation. Room temperature ferromagnetism has been observed. Our analysis demonstrates that (1) C-doped ferromagnetic ZnO can be achieved by an alternative method, i.e., ion implantation, and (2) the chemical involvement of carbon in the ferromagnetism is indirectly proven.