Electron beam-induced thickening of the protective oxide layer around Fe nanoparticles

Wang, C.M.; Baer, Donald R.; Amonette, J. E.; Engelhard, Mark H.; Antony, Jiji; Qiang, You

doi:10.1016/j.ultramic.2007.03.002

Cited by 54 publications

(48 citation statements)

References 27 publications

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“…All the observed crystalline phases before and after ion irradiation of the films are summarized in Table 2). Electron beam-induced thickening of the oxide shell in similar core-shell particles has been observed previously by TEM and attributed to beam-enhanced mass transport by oxygen vacancy creation, 26 but that work did not observe a simultaneous reduction of the iron species as we observe here with ion irradiation. Rather, in our study, the ion irradiation appears to increase the Fe core size, increase 51 and thin films, 52 and could be described as a partially oxidized magnetite.…”

Section: Results and Discussion A Structural Characterizationsupporting

confidence: 74%

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Ion irradiation of Fe-Fe oxide core-shell nanocluster films: Effect of interface on stability of magnetic properties

McCloy

Jiang

Droubay

et al. 2013

Journal of Applied Physics

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A cluster deposition method was used to produce films of loosely aggregated nanoclusters (NC) of Fe core-Fe 3 O 4 shell or fully oxidized Fe 3 O 4 . Films of these NC on Si(100) or MgO(100)/Fe 3 O 4 (100) were irradiated to 10 16 Si 2+ /cm 2 near room temperature using an ion accelerator. Ion irradiation creates structural change in the NC film with corresponding chemical and magnetic changes which depend on the initial oxidation state of the cluster. Films were characterized using magnetometry (hysteresis, first order reversal curves), microscopy (transmission electron, helium ion), and x-ray diffraction. In all cases, the particle sizes increased due to ion irradiation, and when a core of Fe is present, irradiation reduces the oxide shells to lower valent Fe species. These results show that ion irradiated behavior of the nanocluster films depends strongly on the initial nanostructure and chemistry, but in general saturation magnetization decreases slightly.

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Section: Results and Discussion A Structural Characterizationsupporting

confidence: 74%

“…Third, the samples contain a fraction of wustite FeO (4-9 wt%) with crystallites [24][25][26] nm in size, a phase not present in the unirradiated samples. All the observed crystalline phases before and after ion irradiation of the films are summarized in Table 2).…”

Section: Results and Discussion A Structural Characterizationmentioning

confidence: 99%

Ion irradiation of Fe-Fe oxide core-shell nanocluster films: Effect of interface on stability of magnetic properties

McCloy

Jiang

Droubay

et al. 2013

Journal of Applied Physics

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“…The use of an electron beam has been observed to influence the shape and structure of isolated metal nanoparticles, [39,44] to melt or induce recrystallization of Sn particles in silica, [45] and to damage the protective oxide on Fe 0 /FeO x core/shell nanoparticles enabling oxidation in the vacuum within a TEM. [46] In some circumstances electron beam-induced modification of nano-objects may be used to tailor the structure of the objects in a controllable way. This has been demonstrated in the Fe-oxide nanoparticle system.…”

Section: Probe Effectsmentioning

confidence: 99%

Characterization challenges for nanomaterials

Baer

Amonette

Engelhard

et al. 2008

Surface & Interface Analysis

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122

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Nanostructured materials are increasingly subject to nearly every type of chemical and physical analysis possible. Due to their small sizes, there is a significant focus on tools with high spatial resolution. It is also natural to characterize nanomaterials using tools designed to analyze surfaces, because of their high surface area. Regardless of the approach, nanostructured materials present a variety of obstacles to adequate, useful, and needed analysis. Case studies of measurements on ceria and iron metal-core/oxide-shell nanoparticles are used to introduce some of the issues that frequently need to be addressed during analysis of nanostructured materials. We use a combination of tools for routine analysis including X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and x-ray diffraction (XRD) and apply several other methods as needed to obtain essential information. The examples provide an introduction to other issues and complications associated with the analysis of nanostructured materials including particle stability, probe effects, environmental effects, specimen handling, surface coating, contamination, and time.

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“…More importantly, SEM employs relatively low beam energy in comparison to TEM, which is crucial for accurate characterisation of nanoparticles. A recent paper by Wang et al [9] has underlined the importance of addressing the inherent problems associated with TEM imaging, in that the state of the nanoparticles can be easily modified by the high-energy electron beam. According to Wang, there is potential for the high-energy beam to introduce an "electron beam-induced effect" that can result in defect formation, charging of particles and possibly excitation of the surrounding gases.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the de-agglomeration effects of bovine serum albumin on nanoparticles in aqueous suspension

Tantra

Tompkins

Quincey

2010

Colloids and Surfaces B: Biointerfaces

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Electron beam-induced thickening of the protective oxide layer around Fe nanoparticles

Cited by 54 publications

References 27 publications

Ion irradiation of Fe-Fe oxide core-shell nanocluster films: Effect of interface on stability of magnetic properties

Ion irradiation of Fe-Fe oxide core-shell nanocluster films: Effect of interface on stability of magnetic properties

Characterization challenges for nanomaterials

Characterisation of the de-agglomeration effects of bovine serum albumin on nanoparticles in aqueous suspension

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