16 research outputs found
Size-Induced Structural Phase Transition at ∼6.0 nm from Mixed fcc–hcp to Purely fcc Structure in Monodispersed Nickel Nanoparticles
We
have investigated the core issue of atomic lattices in monodispersed
Ni nanoparticles (NPs) of sizes 3.8–10.1 nm using detailed
analysis of X-ray diffraction, synchrotron radiation X-ray absorption
spectroscopy, and magnetization data. This has revealed the very remarkable
coexistence of atomic face-centered cubic (fcc) and hexagonal closed-packed
(hcp) lattices in samples with particle size ≤ 6.0 nm with
the prevalence of only fcc phase beyond this. They are also associated
with reduced coordination number, modified electronic structure, and
surface atom coordination with ligands. Magnetization data furthermore
reveal the coexistence of ferromagnetism and superparamagnetism at
300 K. Considered to be due to dominant roles of ligands, they are
likely to open up far-reaching implications to their future applications