Ferromagnetism in Fe-implanted a-plane ZnO films
03 July 2006
Fe ions of dose 5x10(16) cm(-2) were implanted at 200 keV into a-plane ZnO epitaxial films. The epitaxial quality of the postannealed samples was verified by x-ray diffraction omega-rocking curves and phi scans, whereas x-ray absorption spectroscopy identified the presence of both Fe2+ and Fe3+ ions, as well as changes in their relative concentration during postannealing. Superconducting quantum interference device measurements show that the as-implanted and postannealed films are ferromagnetic at room temperature. The saturation magnetization reduces during annealing possibly due to the decrease in the number of oxygen vacancies. (c) 2006 American Institute of Physics.