| 1. |
- Ludwig, Frank, et al.
(författare)
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Magnetic, Structural, and Particle Size Analysis of Single- and Multi-Core Magnetic Nanoparticles
- 2014
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Ingår i: IEEE Transactions on Magnetics. - 0018-9464 .- 1941-0069. ; 50:11
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Tidskriftsartikel (refereegranskat)abstract
- We have measured and analyzed three different commercial magnetic nanoparticle systems, both multi-core and single-core in nature, with the particle (core) size ranging from 20 to 100 nm. Complementary analysis methods and same characterization techniques were carried out in different labs and the results are compared with each other. The presented results primarily focus on determining the particle size-both the hydrodynamic size and the individual magnetic core size-as well as magnetic and structural properties. The used analysis methods include transmission electron microscopy, static and dynamic magnetization measurements, and Mossbauer spectroscopy. We show that particle (hydrodynamic and core) size parameters can be determined from different analysis techniques and the individual analysis results agree reasonably well. However, in order to compare size parameters precisely determined from different methods and models, it is crucial to establish standardized analysis methods and models to extract reliable parameters from the data.
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| 2. |
- Spiers, H, et al.
(författare)
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Self propagating high temperature synthesis of magnesium zinc ferrites (MgxZn1-xFe2O3): thermal imaging and time resolved X-ray diffraction experiments
- 2004
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501. ; 14:7, s. 1104-1111
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Tidskriftsartikel (refereegranskat)abstract
- Spinel ferrites of the form MgxZn1-xFe2O4 ( x = 0. 0.25, 0.50, 0.75, 1.00) were prepared by self-propagating high-temperature synthesis (SHS) from reactions of iron(III), zinc and magnesium oxides, iron powder and sodium perchlorate. The driving force for the reactions is the oxidation of iron powder. Reactions were carried out in the presence of an external magnetic field of 0.2 or 1.1 T. Reaction velocity and temperatures were obtained by thermal imaging camera. The transformation of reactants to products was studied by time resolved X-ray diffraction using Rietveld refinement for determination of phase percentages. Reactions typically reached temperatures in excess of 1150 degreesC with a timescale of complete conversion of reactant to products of 20 s. All materials were characterised by X-ray powder diffraction (XRD), energy dispersive X-ray analysis (EDXA), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Mossbauer spectroscopy and vibrating sample magnetometry (VSM).
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| 3. |
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| 4. |
- Jonasson, Christian, et al.
(författare)
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Modelling the effect of different core sizes and magnetic interactions inside magnetic nanoparticles on hyperthermia performance
- 2019
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 477, s. 198-202
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental intrinsic loss power (ILP) values, measured at an excitation frequency of 1 MHz and at relatively low field amplitudes of 3.4–9.9 kA/m, as a function of the mean core diameter, for selected magnetic nanoparticles (MNPs). The mean core sizes ranged from ca. 8 nm to 31 nm. Transmission electron microscopy indicated that those with smaller core sizes (less than ca. 22 nm) were single-core MNPs, while those with larger core sizes (ca. 29 nm to 31 nm) were multi-core MNPs. The ILP data showed a peak at core sizes of ca. 20 nm. We show here that this behaviour correlates well with the predicted ILP values obtained using either a non-interacting Debye model, or via dynamic Monte-Carlo simulations, the latter including core-core magnetic interactions for the multi-core particles. This alignment of the models is a consequence of the low field amplitudes used. We also present interesting results showing that the core-core interactions affect the ILP value differently depending on the mean core size.
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| 5. |
- Schier, P., et al.
(författare)
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European Research on Magnetic Nanoparticles for Biomedical Applications : Standardisation Aspects
- 2020
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Ingår i: 21st Polish Conference on Biocybernetics and Biomedical Engineering, PCBBE 2019. - Cham : Springer Verlag. - 9783030298845 ; , s. 316-326
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Konferensbidrag (refereegranskat)abstract
- Magnetic nanoparticles have many applications in biomedicine and other technical areas. Despite their huge economic impact, there are no standardised procedures available to measure their basic magnetic properties. The International Organization for Standardization is working on a series of documents on the definition of characteristics of magnetic nanomaterials. We review previous and ongoing European research projects on characteristics of magnetic nanoparticles and present results of an online survey among European researchers.
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