The Characteristics of the Atomic Structure and Morphology of the Ni-Cores in the Ni/Au Core–Shell Nanoparticles

Influence of NicoreAushell Nanoparticles’ Morphology on Their Magnetic Properties

“…Typical TEM photos of Ni nanocores obtained before covering by Au shells (a–e) and both the hexagonal (rhombus base) and face-centered rhombohedral (hexagon and three larger rhombuses) aspects of the ico-Ni nanocores (f). The interplanar distances d have the indices (110) in the hexagonal aspect and (220) in the rhombohedral one.…”

“…Considering the magnetic properties of Ni core Au shell , it is necessary to take into account their nanoscale, − possible magnetic interactions among the nanoparticles, the state of their Ni-core surface, structure, phase and chemical composition (B x O y , Au–Ni solid solution), and the oxidation process because of the Au-shell breaks. , …”

“…Nevertheless, such a study is absent even for Ni/Co/Fe–Pt core Au shell nanoparticles since there is no their structure characterization in detail and the impact of structure on their magnetic properties in the observed papers. Obviously, Ni core Au shell nanoparticles are the most suitable to be under investigation because of their magnetic characteristics discussed in more detail − and there is the scrutiny of those nanoparticles. − …”

“…Second, spherical Au shells consist of coherent polyhedral pieces of fcc (face-centered cubic) Au lattice (Figure , parts a, b, and i). Third, Ni cores are oxidized to Ni­(OH) 2 in the places of Au-shell breaks (Figure parts d, f, and g). Fourth, the Au-rich solid solution, which volume fraction can rise to 10% in these nanoparticles, is formed on the interface of Ni–Au (Figure , parts a, d, and f, and the ICP-OES data).…”

“…Results on the morphology and composition of the Ni core Au shell –1 nanoparticles: , (a) the decomposition of the main XRD pattern of fcc-Au-shell lattice with the separation of Au phase (estimated crystallite sizes are about 4–7 nm with the shell thickness about 1 nm; this fact marks the polyhedral shell) and SS phase with about 6 wt % of Ni according to the Vegard rule; (b) the TEM graph of an Au shell with the marked inter-row and interatomic distances corresponding to the fcc Au; (c) the TEM graph with the appropriate size distribution of Ni nanocores; (d) the CV curves of Ni core Au shell –1 (1, 2, 3) and an electrodeposited Ni–Au two-layer film (4) capacity when cycled in the range from −0.6 to +0.5 V (1) after cathode reduction at −1.5 V for 2 min (2), and at 0.6 – + 1 V (3, 4); (e) the XPS spectra of boron compounds in the Ni nanocore; (f) the XPS spectra of the Ni core Au shell –1 nanoparticles revealing Au–Ni SS and Ni­(OH) 2 ; (g) the mass spectra of thermo-decomposition products of B impurities in Ni core Au shell –1 and the exothermal effect linked with the ico-fcc transition in Ni nanocores; (h) the CSL model calculated (1–4) and experimental (5) patterns of the diffraction maximum of Ni nanoparticles, inseta diffraction scheme; (i) the TEM micrograph of the Ni core Au shell –1 nanoparticles and their size distribution bar chart; (j) the calculated and experimental diffraction patterns of ico-Ni nanoparticles (Cu-irradiation).…”