Synthesis and magnetic properties of nickel three-dimensional superlattice structure

High monodisperse nickel nanoparticles of 13 nm were successfully synthesised based on reduction of common nickel salts. Further annealing process prompted the formation of magnetic superlattices. The morphological features characterised by field emission scanning electron microscopy showed that the Ni nanoparticles self-assembled periodically and formed close-packed arrays. The results of magnetic hysteresis loops showed that the sample exhibited improved magnetic properties compared with those of other bigger nanoparticles. The Curie temperature of the sample was about 596 K, lower than that of the bulk material, which is discussed in terms of the finite-size effects.