Darja Lisjak (Author), Iztok Arčon (Author), Matic Poberžnik (Author), Gabriela Herrero‑Saboya (Author), Ali Tufani (Author), Andraž Mavrič (Author), Matjaž Valant (Author), Patricija Hribar (Author), Alenka Mertelj (Author), Darko Makovec (Author), Layla Martin‑Samos (Author)

Abstract

Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1–4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe–phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.

Keywords

barium hexaferrite;Fe XANES;EXAFS;magnetic nanoparticles;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 537
COBISS: 138678531 Link will open in a new window
ISSN: 2045-2322
Views: 648
Downloads: 2
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Other data

Type (COBISS): Not categorized
Source comment: Nasl. z nasl. zaslona; Opis vira z dne 20. 1. 2023;
Pages: str. 1092-1-1092-13
Volume: ǂVol. ǂ13
Chronology: 2023
DOI: 10.1038/s41598-023-28431-4
ID: 21815645