Sputtering of size-tunable oxidized Fe nanoparticles by gas flow method
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Sputtering of size‑tunable oxidized Fe nanoparticles by gas flow method E. A. Dawi1 · A. Haj Ismail1 · A. AbdelKader1 · A. A. Karar2 Received: 9 January 2020 / Accepted: 24 March 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Systematic optimization of sputter parameters allowed the growth of size-tunable ferric nanoparticles on glassy-carbon substrates using gas flow sputtering technique. By variation of the sputtering pressure and particle aggregation length, Fe nanoparticles with mean diameter ranging between 20 and 150 nm were formed. Several physical and optical techniques were used to examine the size and morphology of the nanoparticles. While nanoparticles were revealed as spherical, their crystalline structure was detected only for the hematite type of Fe. By fostering the sputtering growth using Ar and He admixture flow, density variation within the grown particles was established, offering a strategy to overcome the slow growth rates in the sputter sources. Magnetization measurements taken at room temperature did not show evidence of the impact of size on the magnetic properties of the nanoparticles. Thus, saturation magnetization and coercivity values were obtained. Measurements of the linear optical properties of the sputtered nanoparticles showed a general decrease in extinction with decreasing nanoparticle size. Monotonically decreasing spectra were observed, except for a shoulder in the 300–400 nm range. Keywords Fe nanoparticles · Sputtering · Sputtering pressure · Aggregation length · Gas flow · Magnetization
1 Introduction Nanoparticles (NPs) currently attract much scientific interest because their physical [1–3] and chemical [4] properties differ from their bulk counterparts. In recent years, great attention has been paid to ferric nanoparticles (Fe NPs) due to their exclusive magnetic [5, 6] and catalytic [7] properties. Owing to their unique properties, such NPs are considered for use in broad application areas, such as biomedicine, e.g., in magnetic hyperthermia [8], magnetic resonance imaging (MRI) contrast agents [9], drug delivery [10] and pollutant metal remediation [11, 12]. These properties depend significantly on NP size and shape, such that modifying one of these parameters provides a way to control the properties of the material. An effective practice of such size-dependent properties requires that NPs must * E. A. Dawi [email protected] 1
Department of Mathematics and Science, College of Humanities and Sciences, Ajman University, PO Box, 346, Ajman, United Arab Emirates
Edith Cowan University, 270 Joondalup Drive, Joondalup, WA 6027, Australia
2
be prepared with a predefined, usually narrow size distribution. Besides, their degree of clustering has a decisive influence on the quality of the final product made from these NPs. In the literature, a variety of different techniques have been reported on the synthesis, fabrication and growth of Fe NPs using dry and wet processes, including evaporation [13] and thermal decomposition of organoiron an
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