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Issue 15, 2018
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Tuning the structure and magnetic behavior of Ni–Ir-based nanoparticles in ionic liquids

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Abstract

We report on a simple preparation of extremely small diameter (ca. 2 nm) Ni–Ir-based NPs using Ni(COD)2 and [Ir(COD)OCH3]2 in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIm·NTf2). The prepared NPs had either core–shell-like or alloy-like structures with the presence of Ni,Ir-oxides, depending on the synthetic approach. X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), and magnetic measurements are combined to describe the influence of nanostructure on the magnetic behavior of these nanosystems. The present findings reveal that the alloy NPs display a disordered magnetic state, similar to a spin glass (SG)-like system (Tf = 7.2 K). Core–shell NPs are formed by a magnetically blocked/unblocked core with a magnetically disordered shell as deduced from the two magnetic responses peaking at TB = 75 K and Tf = 5.8 K. Coupling at the core–shell interface leads to an exchange bias revealed at low temperature as horizontal shifts in the hysteresis loops of 0.12 kOe at 2 K.

Graphical abstract: Tuning the structure and magnetic behavior of Ni–Ir-based nanoparticles in ionic liquids

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Publication details

The article was received on 09 Jan 2018, accepted on 10 Mar 2018 and first published on 13 Mar 2018


Article type: Paper
DOI: 10.1039/C8CP00164B
Citation: Phys. Chem. Chem. Phys., 2018,20, 10247-10257
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    Tuning the structure and magnetic behavior of Ni–Ir-based nanoparticles in ionic liquids

    K. I. M. da Silva, F. Bernardi, G. Abarca, D. L. Baptista, M. J. Leite Santos, L. Fernández Barquín, J. Dupont and I. de Pedro, Phys. Chem. Chem. Phys., 2018, 20, 10247
    DOI: 10.1039/C8CP00164B

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