scholarly journals Plasma-assisted synthesis and high-resolution characterization of anisotropic elemental and bimetallic core–shell magnetic nanoparticles

2014 ◽  
Vol 5 ◽  
pp. 466-475 ◽  
Author(s):  
M Hennes ◽  
A Lotnyk ◽  
S G Mayr
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Magnetic Core ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Gas Condensation ◽  
Pulsed Dc ◽  
Transmission Electron ◽  
Core Shell Nanoparticles ◽  
Kinetic Gas Theory

Magnetically anisotropic as well as magnetic core–shell nanoparticles (CS-NPs) with controllable properties are highly desirable in a broad range of applications. With this background, a setup for the synthesis of heterostructured magnetic core–shell nanoparticles, which relies on (optionally pulsed) DC plasma gas condensation has been developed. We demonstrate the synthesis of elemental nickel nanoparticles with highly tunable sizes and shapes and Ni@Cu CS-NPs with an average shell thickness of 10 nm as determined with scanning electron microscopy, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy measurements. An analytical model that relies on classical kinetic gas theory is used to describe the deposition of Cu shell atoms on top of existing Ni cores. Its predictive power and possible implications for the growth of heterostructured NP in gas condensation processes are discussed.

Preparation and Characterization of Nickel(Ni)-Silver(Ag) Core-Shell Nanoparticles for Conductive Pastes

2012 ◽  
Vol 531 ◽  
pp. 211-214 ◽  
Author(s):  
Jun Jie Jing ◽  
Ji Min Xie ◽  
Hui Ru Qin ◽  
Wen Hua Li ◽  
Ming Mei Zhang
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Water Solution ◽  
Average Diameter ◽  
Core Shell ◽  
Ni Nanoparticles ◽  
Shell Nanoparticles ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Core Shell Nanoparticles

Nickel(Ni)-silver(Ag) core-shell nanoparticles with different shell thickness were synthesized with Ni nanoparticles by liquid phase reduction technique form water solution. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and inductively coupled plasma spectroscopy (ICP). The results showed that the Ni nanoparticles are in sphere shape and the average diameter is 104nm , the nickel(Ni)-silver(Ag) core-shell nanoparticles has good crystallinity and the thinkness of Ag nanoshells could be effectively controlled by changing the concentration of silver nitrate. The product can be used for nickel-based conductive paste preparation because of the surface character of Ag and the magnetic property of Ni

In situ TEM observation of Au–Cu2O core–shell growth in liquids

Nanoscale ◽  
2019 ◽  
Vol 11 (21) ◽  
pp. 10486-10492 ◽  
Author(s):  
Fu-Chun Chen ◽  
Jui-Yuan Chen ◽  
Ya-Hsuan Lin ◽  
Ming-Yu Kuo ◽  
Yung-Jung Hsu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Shell Growth ◽  
Core Shell ◽  
In Situ Tem ◽  
Shell Nanoparticles ◽  
Transmission Electron ◽  
Liquid Cell ◽  
Different Shapes ◽  
Core Shell Nanoparticles

The formation of different shapes Au–Cu2O core–shell nanoparticles was investigated by in situ liquid cell transmission electron microscopy (LCTEM).

scholarly journals Hybrid Nanoelectronic-magnetic Device with Magnetoresistive Effect for logic integrated platforms in Spintronics

2019 ◽  
Author(s):  
Ovidiu Crisan ◽  
Alina Daniela Crisan ◽  
Catalin Romeo Luculescu
Keyword(s):  
Magnetic Core ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Magnetic Device ◽  
Hybrid Device ◽  
Optical Scanning ◽  
Nanosized Materials ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Core Shell Nanoparticles

We propose a concept of hybrid nanoelectronic-magnetic device for logic integrated platforms made of magnetic core-shell nanoparticles deposited onto prepatterned Si (111) substrate with basic logic circuitry made of metallic conductive lines. The synthesis of magnetic material and the creation of nanoelectronic prepatterned interdigitated die is reported and its capabilities are demonstrated in terms of magnetotransport properties. The laser pyrolysis method is employed in order to synthesize magnetic core-shell Fe / FeC nanoparticles with sizes between 12 – 15 nm. E-beam lithography has been used in order to design and execute two different layouts of interdigitated die, prepatterned with logic capacity, one with two pads and 50 microns thick conductive metallic lines, another one with 4 pads and parallel 5 microns thick conductive lines separated by 5 microns thick spacer. The as-obtained structures are morphologically characterized by means of optical, scanning and transmission electron microscopies. As-synthesized core-shell nanoparticles have been magnetically characterized inasmuch as the hybrid device obtained by depositing centrifugated and dispersed core-shell nanoparticles from liquid carrier solutions. For the first time, a significant giant magnetoresistive (GMR) effect has been observed and measured for the hybrid architectured device made of Fe / FeC nanosized materials on pre-patterned interdigitated die. A ∆R/R of 8% at 4.2 K has been measured from conductivity-in-plane electron transport measurements. This opens possibilities for the use of such devices as arrays of nanosensors and in spintronic applications.

Facile Fabrication of Antibacterial Core–Shell Nanoparticles Based on PHMG Oligomers and PAA Networks via Template Polymerization

2014 ◽  
Vol 67 (1) ◽  
pp. 142 ◽  
Author(s):  
You Wei Zhang ◽  
Yan Chen ◽  
Jiong Xin Zhao
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Acrylic Acid ◽  
Electrostatic Interactions ◽  
Minimum Size ◽  
Core Shell ◽  
Nanoparticle Dispersion ◽  
Shell Nanoparticles ◽  
Transmission Electron ◽  
Core Shell Nanoparticles

Antibacterial core–shell nanoparticles based on poly(hexamethylene guanidine hydrochloride) (PHMG) oligomers and poly(acrylic acid) (PAA) networks are efficiently fabricated via a facile one-step co-polymerization of acrylic acid and N,N′-methylenebisacrylamide on PHMG templates in aqueous solution. Dynamic light scattering, Fourier-transform infrared spectroscopy, and transmission electron microscopy observations were used to characterize the size, morphology, and structure of the nanoparticles, as well as the interactions between the components. Also, the stability of the nanoparticle dispersion against storage, pH value, salt, and temperature was investigated. The results show that the crosslinked PAA/PHMG nanoparticles are stabilized by electrostatic interactions. The core–shell structure of the nanoparticles was confirmed by transmission electron microscopy observation. The size of the nanoparticles increases substantially with extension of storage or with increase of the salt concentration. The nanoparticle dispersion is stable in a pH range of 2.0–4.0. The size change of the nanoparticles with pH of the medium is parabolic, and the minimum size is reached at pH 3.0. A rise of temperature leads to a slight and recoverable size increase of the nanoparticles. Antibacterial efficiency was evaluated quantitatively against Escherichia coli and Staphylococcus aureus by the plating method according to Standard JC/T 897–2002. The antibacterial activity against these two bacteria are both above 99.0 % at a nanoparticle concentration of 5 mg mL–1. This makes the nanoparticle dispersion a good candidate for the application of antibacterial water-based coatings and textiles coating.

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