Preparation of tunable-sized iron nanoparticles based on magnetic manipulation in inert gas condensation (IGC)

Abstract

Iron nanoparticles (NPs) prepared by inert gas condensation were studied using high resolution transmission electron microscopy and Wulff construction shape analysis. The NP size and shape show strong dependence on the magnetic field above the target surface. The effect of the magnetic field could be tuned by adjusting the thickness of the protective backing plate positioned in-between the target and the magnetron head. With increasing backing plate thickness, the particle size decreases and the NP morphologies evolve from faceted to close-to-spherical polyhedral shapes. Moreover, with changes in size and shape, the particle structure also varies so that the NPs exhibit: (i) a core-shell structure for the faceted NPs with size ∼15–24 nm; (ii) a core-shell structure for the close-to-spherical NPs with size ∼8–15 nm; and (iii) a fully oxidized uniform structure for NPs with sizes less than ∼8 nm having a void in the center due to the Kirkendall effect. The decrease of NP size with the increasing backing plate thickness can be attributed to a reduced magnetic field strength above the iron target surface combined with a reduced magnetic field confinement. These results pave the way to drastically control the NP size and shape in a simple manner without any other adjustment of the aggregation volume within the deposition system.

Magnetic Iron Oxide Nanoparticles: Synthesis, Characterization and Functionalization for Biomedical Applications in the Central Nervous System

“…The selected literature was classified into four main groups:Methods of synthesis of IONPs [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56]Characterization of IONPs [57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,…”

“…Methods of synthesis of IONPs [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56]…”

“…Afterwards, a small amount of oxygen is introduced in the deposition chamber to allow the oxidation (Fe 3 O 4 ) of NP surface, thus leading to the formation of iron/iron-oxide core-shell nanoclusters [45]. By adjusting the physical parameters of the process—such as the pressure in the aggregation chamber, the ratio of He to Ar gas, and the magnetron-sputter power—NP mean diameter can be tuned from 1 to 100 nm [46,47]. Notably, also NP ferromagnetic properties can be changed by ion irradiation [48,49,50].…”

Atomic-scale structure and chemical sensing application of ultrasmall size-selected Pt nanoparticles supported on SnO2

“…Magnetron sputtering inert-gas condensation, a versatile technique for the growth of single-and multicomponent nanoparticles with controlled size and morphology, [21][22][23] was employed for the deposition of pre-formed, size-selected Pt nanoparticles. A wide range of nanoparticle functionalities has been achieved with this method, e.g., percolating nanoparticle films for chemoresistive sensing, [24][25][26][27][28][29][30] nanoparticle-decorated metal oxide nanowire devices for chemoresistive sensing, [31][32][33] supported nanoparticles for catalysis and electrochemistry, [34][35][36][37] magnetic nanoparticles, 30,[38][39][40] nanoparticles embedded in multi-layered anodes for lithium ion batteries 41 and nanoportals for hydrogen storage applications. 42 Here, we demonstrate a new approach for the surface functionalization of micro-machined chemical sensor devices realized in complementary metal-oxide-semiconductor (CMOS) technology, in particular by depositing ultrasmall Pt nanocatalysts by magnetron sputtering inert-gas condensation onto nanocrystalline SnO 2 thin films integrated on a suspended microhotplate platform.…”

Effect of magnetic field on the formation of Cu nanoparticles during magnetron sputtering in the gas aggregation cluster source

“…This consequently affects the size and distribution of the resulting NPs. Xing et al obtained Fe and Fe oxide NPs with a tunable size, shape and structure dependant on the MF configuration. In this case, variation of the MF was realized by changing the interspace distance between the magnetron surface and the sputtering target by introducing nonmagnetic metal backing plates.…”