Structural and magnetic properties of Yb-implanted GaN

N-type, p-type and unintentionally-doped GaN were implanted with Yb ions by double energy ion implantation and the samples were annealed at 900 degrees C. The structural and magnetic properties of the samples have been studied by high-resolution X-ray diffraction (HRXRD), Raman scattering and with a superconducting quantum interference device (SQUID). No second phase has been observed and implantation induced defects can not be completely removed by rapid thermal annealing. The annealed samples show magnetic anisotropy and clear ferromagnetic behavior at room temperature. P-, u- and n-GaN: Yb samples show an effective magnetic moment of 1.60, 1.24 and 0.59 mu B/Yb, respectively.