Journal of Magnetism and Magnetic Materials

co gn ma of W et of shap ing i ide chain isolated and collective magnetic behavior. nanocrystals from being oxidized and controls the determining their self-assembly. Small (diameter, When compared to the thermal energy, kBT it deter-ARTICLE IN PRESSmines the magnetic stability of the nanocrystals; typically, the magnetic relaxation time depends expo-nentially on the particle volume [4]. As a result, at room temperature, particles smaller than a critical size (diametero10 nm for Co) have magnetic dipol