Structure, optical, and magnetic properties of sputtered manganese and nitrogen-codoped ZnO films

To realize the hole-mediated ferromagnetism, manganese and nitrogen-codoped ZnO (Zn1-xMnxO:N) films were prepared on sapphire (0001) by reactive radio-frequency (rf) magnetron sputtering from Zn0.97Mn0.03O ceramic targets using N-2 gas. X-ray photon spectra reveal that the doped Mn ions are mainly in divalent states and the coexistence of O-Zn and N-Zn bonds in the films. According to the absorption spectra, the band gap of Zn0.97Mn0.03O:N films is about 3.15 eV, which is slightly lower than that of ZnO films (3.20 eV). Compared with Zn0.97Mn0.03O films, ferromagnetic behavior of Zn0.97Mn0.03O:N films were significantly changed with a coercivity of about 70 Oe, a saturation magnetization of 0.92 mu(B)/Mn2+ and a remanance over 0.15 mu(B)/Mn2+ at 300 K, while at 10 K, they increased to be about 110 Oe, 1.05 mu(B)/Mn2+ and 0.23 mu(B)/Mn2+, respectively. However, rapid thermal annealing treatment in pure oxygen results in a significant decrease on the magnetic properties of the films. (c) 2006 American Institute of Physics.