Synthesis and structure of magnetic core-shell Ni-Ce nanocomposite particles

摘要

A new type of magnetic core-shell Ni-Ce nanocomposite particles (15-50 nm) is presented. SEM observations suggest the particles are strongly ferromagnetic, interacting with ordered chain-like features. Typical HR-TEM images demonstrate that many planar defects (nanotwins and stacking faults) exist in the surface shell and large Ni core zone (10-40 nm) of the particles; the inner shell layers (4-6 nm) consist of NiCe alloy and the outermost shell is NiO. Nano-diffraction patterns show an indication of well-defined spots characteristic of nanocomposite materials, of which certain crystal facet orientation relationships between orthorhombic [111] of NiCe and cubic [311] of Ni_2Ce, face-center crystal [222] of NiO, cubic [111] of nickel have been identified. This confirms the nature of this core-shell nanocomposite particle.