High coercivity and exchange coupling of Ni/NiO nanocomposite film

A coercivity of 2.4 kOe was achieved at room temperature after magnetic annealing a pure Ni film at 650 K for 20 min under O-2 partial pressure of 0.001 torr. The interface structure of Ni/NiO during the formation of NiO under magnetic field and the small grains may be responsible for the large coercivity. Additionally, the surface NiO, dipolar interaction of Ni particles, and the composition of NiO inside the film may affect the coercivity as well. C 2005 American Institute of Physics.