| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Ahlburg, Jakob Voldum
Aarhus University
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (21/21 displayed)
- 2022In-depth investigations of size and occupancies in cobalt ferrite nanoparticles by joint Rietveld refinements of X-ray and neutron powder diffraction datacitations
- 2022Combined characterization approaches to investigate magnetostructural effects in exchange-spring ferrite nanocomposite magnetscitations
- 2021Synthesis and Characterization of a Magnetic Ceramic Using an Easily Accessible Scale Setupcitations
- 2020Exploring the direct synthesis of exchange-spring nanocomposites by reduction of CoFe 2 O 4 spinel nanoparticles using in situ neutron diffractioncitations
- 2020Exploring the direct synthesis of exchange-spring nanocomposites by reduction of CoFe2O4 spinel nanoparticles using in situ neutron diffractioncitations
- 2020Realising Sample Environments for X-ray and Neutron Powder Diffraction
- 2020Ultra-Fast Heating – Induction furnace for POLARIS
- 2019Novel fast heating furnaces for in situ powder neutron diffraction
- 2019Structure and magnetic properties of W-type hexaferritescitations
- 2019Magnetostructural effects in exchange-spring nanocomposite magnets probed by combined X-ray & neutron scattering
- 2019Novel in situ powder neutron diffraction setups – The creation of a modern magnetic compound
- 2019Air-heated solid–gas reaction setup for in situ neutron powder diffractioncitations
- 2019In Situ In-House Powder X-ray Diffraction Study of Zero-Valent Copper Formation in Supercritical Methanolcitations
- 2019In Situ In-House Powder X-ray Diffraction Study of Zero-Valent Copper Formation in Supercritical Methanolcitations
- 2019Laboratory setup for rapid in situ powder X-ray diffraction elucidating Ni particle formation in supercritical methanolcitations
- 2018X-ray and neutron diffraction magnetostructural investigations on exchange-coupled nanocomposite magnets
- 2018Koercivitetsforbedring af strontium hexaferrit nano-krystallitter gennem morfologikontrolleret udglødning. ; Coercivity enhancement of strontium hexaferrite nano-crystallites through morphology controlled annealingcitations
- 2018Approaching Ferrite-Based Exchange-Coupled Nanocomposites as Permanent Magnetscitations
- 2018Coercivity enhancement of strontium hexaferrite nano-crystallites through morphology controlled annealingcitations
- 2017Optimization of spring exchange coupled ferrites, studied by in situ neutron diffraction.
- 2015Particle size optimization of SrFe12O19 magnetic nanoparticles
Places of action
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document
Magnetostructural effects in exchange-spring nanocomposite magnets probed by combined X-ray & neutron scattering
Abstract
<p class="MsoNoSpacing" style="text-align:justify">An ideal permanent magnet should be highly resistant to demagnetization (high coercivity <i>H</i><sub>C</sub>) and have a high value of maximum internal magnetization (high saturation magnetization <i>M</i><sub>S</sub>). In the real world, a single-phase magnet might not simultaneously possess high values of these magnetic properties. It is usually observed that rare-earth-free permanent magnets have either high <i>H</i><sub>C</sub>with low <i>M</i><sub>S</sub> (‘hard’ magnet– hard to demagnetize) or, low <i>H</i><sub>C</sub>with high <i>M</i><sub>S</sub> (‘soft’ magnet). The hexaferrite compound SrFe<sub>12</sub>O<sub>19</sub> has relatively high <i>H</i><sub>C</sub> (due to pronounced magnetocrystalline anisotropy) – making it a ‘hard magnetic’ phase, but a higher <i>M</i><sub>S</sub> value would be highly appreciated.<sup>[1]</sup> Spinel ferrites (AB<sub>2</sub>O<sub>4</sub>type) on the other hand, are ‘soft magnetic’ phases <i>i.e. </i>low <i>H</i><sub>C</sub>, but potentially strongly magnetic. Enhancement of <i>H</i><sub>C</sub> and <i>M</i><sub>S</sub>values simultaneously could be achieved by the mixing of two different nanomagnetic phases (hard-soft composite) – known as an exchange-spring nanocomposite.<sup>[2,3]</sup> The resultant magnetic properties of such composites would be hierarchically emergent – arising from the underlying atomic structure, via the nanoscale morphology of the individual particles, to the microscopic structural coupling of the different phases. While various studies have focused on the synthesis of exchange-spring magnets and their magnetic characterizations, detailed structural investigations are limited.<sup>[3–5]</sup> We report a comparative investigation on exchange-spring nanocomposites of SrFe<sub>12</sub>O<sub>19</sub>(SFO – hard magnet) and Zn<sub>0.2</sub>Co<sub>0.8</sub>Fe<sub>2</sub>O<sub>4</sub>(ZCFO – soft magnet) prepared by two different synthesis routes: mechanical powder mixing and sol-gel coating. <i>M</i>-<i>H</i> loops from VSM magnetometry showed a dependence of the exchange-coupling behavior on the technique used for nanocomposite formation. Crystallographic and magnetic structure of the samples were analyzed by combined Rietveld refinement of data from synchrotron X-ray diffraction (SR-XRD performed at MS X04SA beamline @ SLS) & thermal neutron powder diffraction (NPD performed using HRPT diffractometer at SINQ spallation source @ PSI). The difference in the scattering interaction for X-rays and neutrons allowed for complementary, robust & accurate structural analysis.<sup>[5,6]</sup> Combined Rietveldrefinement of SR-XRD and NPD data of the nanocomposites enabled extraction of accurate values for lattice parameters, atomic positions, thermal motion, cation distribution, magnetic moments and microstructure. A detailed understanding of these correlated magnetostructural properties would be instrumental towards improving the performance of permanent magnets based on exchange-spring nanocomposites.</p><p class="MsoNoSpacing" style="text-align:justify"><br/></p><p class="MsoNoSpacing" style="text-align:justify">References:</p><p class="MsoNormal" style="margin-left:32.0pt;text-indent:-32.0pt;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none">[1] R. C. Pullar, <i>Prog.</i><i>Mater.Sci.</i> <b>2012</b>,<i>57</i>, 1191.</p><p class="MsoNormal" style="margin-left:32.0pt;text-indent:-32.0pt;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none">[2] E.F. Kneller, R. Hawig, <i>IEEE Trans. Magn.</i> <b>1991</b>, <i>27</i>, 3588.</p><p class="MsoNormal" style="margin-left:32.0pt;text-indent:-32.0pt;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none">[3] F. Liu, Y.Hou, S. Gao, <i>Chem. Soc. Rev.</i> <b>2014</b>, <i>43</i>, 8098.</p><p class="MsoNormal" style="margin-left:32.0pt;text-indent:-32.0pt;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none">[4] S. Hirosawa, <i>J.Magn. Soc. Japan</i> <b>2015</b>, <i>39</i>, 85.</p><p class="MsoNormal" style="margin-left:32.0pt;text-indent:-32.0pt;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none">[5] S. M. Yusuf,A. Kumar, <i>Appl. Phys. Rev.</i> <b>2017</b>, <i>4</i>, 031303.</p><p class="MsoNormal" style="margin-left:32.0pt;text-indent:-32.0pt;mso-pagination:none;mso-layout-grid-align:none;text-autospace:none">[6] E. Solano, C.Frontera, T. Puig, X. Obradors, S. Ricart, J. Ros, <i>J. Appl. Crystallogr.</i><b>2014</b>, <i>47</i>, 414.</p>