Abstract :
Size effect on the magnetization and the coercivity of nanocrystalline Ni films has been examined at room temperature. Agreement between modeling predictions and measurements reveals that the size-suppressed magnetization results from the drop of spin–spin exchange energy due to the coordination number (CN) imperfection of atoms near the surface edges, and that the size-enhanced coercivity arises from intergrain interaction that is proportional to the inverse of particle size. Findings herewith and reported previously on the size-induced lattice contraction and Curie temperature suppression evidence the significance of atomic CN imperfection on the unusual behavior of a ferromagnetic nanosolid.
