Structure and magnetic properties of Ni-doped AlN films

We report the crystal structure and magnetic properties of Al1-xNixN films with 0 ≤ x ≤ 0.032 deposited on Si (100) substrates by radio frequency reactive sputtering. X-ray diffractometry, x-ray photoemission spectroscopy, and x-ray absorption fine structure analysis clearly showed that Ni atoms were successfully incorporated into AlN, while the crystal structure of the films was maintained. All the doped samples exhibited ferromagnetism both at 5 K and 300 K. The saturation magnetizations (Ms) and coercive fields (Hc) tended to decrease as Ni concentration increased from 0.019 to 0.032, the maximum Ms obtained at 5 K and 300 K were about 0.025 and 0.014 emu/g, respectively, and the corresponding Hc were 208 and 60 Oe. Temperature dependence of remanent magnetization showed that the ferromagnetic transition temperature was beyond 300 K.