Ferromagnetic-like behavior of ultrafine NiO nanocrystallites

Ultrafine NiO nanocrystallites (NCs) with grain size of 5 nm have been synthesized by vacuum thermolysis method. These NCs exhibit a ferromagnetic-like behavior, and a large coercivity of 327.14 kA/m exists together with a large exchange bias field of 148.48 kA/m at 4.2 K. A large net magnetization of 205.72 mu(B) per particle is evaluated for the 5 nit NCs. The ferromagnetic-like magnetic properties are attributed to the combined effects of missing bonds and the lattice distortion. (C) 2003 Elsevier B.V. All rights reserved.