Frequency- and magnetic-field-dependent properties of ordered magnetic nanoparticle arrangements
| Autor: | T. Hache, Detlev M. Hofmann, Peter J. Klar, Matthias T. Elm, Helmut Schultheiss, Nils Neugebauer, Christian Heiliger |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Center (category theory) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics Light scattering Magnetic field Brillouin zone Laser linewidth 0103 physical sciences Magnetic nanoparticles 010306 general physics 0210 nano-technology Electron-beam lithography Excitation |
| Zdroj: | Publication date: 2020-11-09 Open accessDOI: 10.14278/rodare.577Versions: 10.14278/rodare.578License: CC-BY-4.0 Physical Review B 103(2021), 094438 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.103.094438 |
| Popis: | We present investigations of the frequency and magnetic field dependent properties of ordered magnetic nanoparticles (MNPs) arrangements consisting of magnetite (${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$) nanoparticles with an average diameter of 20 nm by employing micro Brillouin light scattering microscopy. We utilized electron beam lithography to prepare hexagonally arranged, circularly shaped MNP assemblies consisting of a single layer of MNPs using a variant of the Langmuir-Blodgett technique. By comparing the results with nonstructured, layered superlattices of MNPs, further insight into the influence of size and geometry of the arrangement on the collective magnetic properties is obtained. We show that at low static external field strengths, two signals occur in frequency dependent measurements for both nonstructured and structured assemblies. Increasing the static external field strength results in a sharpening of the main signal, while the satellite signal decreases in its intensity and increases in its linewidth. The occurrence of multiple signals at low external field strengths is also confirmed by sweeping the static external field and keeping the excitation frequency constant. Furthermore, two-dimensional spatial mapping of the resonances reveals that the main and the satellite signal originate from the center and the edge, respectively, of a single circular MNP assembly. Micromagnetic simulations confirm these assignments and the dependence of the two signals on the static external field strength, justifying an interpretation of the observed characteristics in terms of different local environments of MNPs forming the MNP assembly. |
| Databáze: | OpenAIRE |
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