The structural and magnetic properties, as well
as the mechanism of magnetization, of Ni-implanted AlN
films were studied. AlN was deposited on Al 2 O 3 substrates
by metalorganic chemical vapor deposition (MOCVD),
and subsequently Ni ions were implanted into the AlN
films by Metal Vapor Arc (MEVVA) sources at an energy
of 100 keV for 3 h. The films were annealed at 900°C for 1
h in the furnace in order to transfer the Ni ions from
interstitial sites to substitutional sites in AlN, thus
activating the Ni 3+ ions. Characterizations were performed
in situ using X-ray diffraction (XRD), X-ray photoemis-
sion spectroscopy (XPS), and vibrating sample magneto-
metry (VSM), which showed that the films have a wurtzite
structure without the formation of a secondary phase after
implanting and annealing. Ni ions were successfully
implanted into substitutional sites of AlN films, and the
chemical bonding states are Ni-N. The apparent hysteresis
loops prove that the films exhibited magnetism at 300 K.
The room temperature (RT) saturation magnetization
moment (M s ) and coercivity (H c ) values were about 0.36
emu/g and 35.29 Oe, respectively. From the first-principles
calculation, a total magnetic moment of 2.99 μB per
supercell is expected, and the local magnetic moment of a
NiN 4 tetrahedron, 2.45 μB, makes the primary contribu-
tion. The doped Ni atom hybridizes with four nearby N
atoms in a NiN 4 tetrahedron; then the electrons of the N
atoms are spin-polarized and couple with the electrons of
the Ni atom with strong magnetization, which results in
magnetism. Therefore, the p-d exchange mechanism
between Ni-3d and N-2p can be the origin of the
magnetism. It is expected that these room temperature,
ferromagnetic, Ni-doped AlN films will have many
potential applications as diluted magnetic semiconductors.

• Diluted magnetic characteristics of Ni-doped AlN films via ion implantation