Air-Stable Anisotropic Monocrystalline Nickel Nanowires Characterized Using Electron Holography

Abstract

Nickel is capable of discharging electric and magnetic shocks in aerospace materials thanks to its conductivity and magnetism. Nickel nanowires are especially desirable for such an application as electronic percolation can be achieved without significantly increasing the weight of the composite material. In this work, single-crystal nickel nanowires possessing a homogeneous magnetic field are produced via a metal-organic precursor decomposition synthesis in solution. The nickel wires are 20 nm in width and 1-2 μm in length. The high anisotropy is attained through a combination of preferential crystal growth in the ⟨100⟩ direction and surfactant templating using hexadecylamine and stearic acid. The organic template ligands protect the nickel from oxidation, even after months of exposure to ambient conditions. These materials were studied using electron holography to characterize their magnetic properties. These thin nanowires display homogeneous ferromagnetism with a magnetic saturation (517 ± 80 emu cm), which is nearly equivalent to that of bulk nickel (557 emu cm). Nickel nanowires were incorporated into carbon composite test pieces and were shown to dramatically improve the electric discharge properties of the composite material.

Faceted Branched Nickel Nanoparticles with Tunable Branch Length for High‐Activity Electrocatalytic Oxidation of Biomass

“…This growth mechanism can be due to the strong binding of amine surfactant to {101 0} facets or kinetically preferred growth along the c-axis. [25,26] The above set of experiments demonstrates the high level of control achieved in this synthesis strategy, with tunable branch lengths while maintaining branch widths below 25 nm. The ability to control the branch length without altering the width of branches enables tuning of the ratio of {101 0} facets on the sides and {0001} on the tips (Figure 2 b).…”

“…This indicates the majority of the growth is along the c ‐axis making longer branches. This growth mechanism can be due to the strong binding of amine surfactant to {10 0} facets or kinetically preferred growth along the c ‐axis . The above set of experiments demonstrates the high level of control achieved in this synthesis strategy, with tunable branch lengths while maintaining branch widths below 25 nm.…”

Perspective: Ferromagnetic Liquids

“…The overarching questions regarding magnetic sensing with ferromagnetic liquids is the detection of physical changes that is conveniently done by magneto-resistance measurements in exchange-coupled metallic materials. For these applications, electro-chemical plating using a porous alumina template and strain-engineering rolled-up nanotech facilitating intrinsic strain gradients have been employed [60,61] and refined to synthesize nano-rods, nano-tubes and multi-segmented specimens [64][65][66][67][68][69][70] with variable diameter (<50 nm), and microtubules with tailored magnetization configuration [71,72] that achieve unprecedented sensitivity based on the giant magneto-impedance effect [73].…”

Prominence of the Instability of a Stabilizing Agent in the Changes in Physical State of a Hybrid Nanomaterial

“…Stabilizing agents (SAs) used for the preparation of nanoparticles in solution are of tremendous importance for the control of their size and shape [1–7] as well as for their colloidal stability [8–11] . Their role on the nanomaterial's properties is also established for magnetic, [8,12] optical, [13–15] thermoelectric, [16] catalytic properties, [17–21] and biocompatibility [22–24] .…”