Oberdick, Samuel D., Abdelgawad, Ahmed, Moya, Carlos et al. (13 more authors) (2018) Spin canting across core/shell Fe3O4/MnxFe3−xO4 nanoparticles. Scientific Reports. p. 3425. ISSN 2045-2322
Abstract
Magnetic nanoparticles (MNPs) have become increasingly important in biomedical applications like magnetic imaging and hyperthermia based cancer treatment. Understanding their magnetic spin configurations is important for optimizing these applications. The measured magnetization of MNPs can be significantly lower than bulk counterparts, often due to canted spins. This has previously been presumed to be a surface effect, where reduced exchange allows spins closest to the nanoparticle surface to deviate locally from collinear structures. We demonstrate that intraparticle effects can induce spin canting throughout a MNP via the Dzyaloshinskii-Moriya interaction (DMI). We study ~7.4 nm diameter, core/shell Fe3O4/MnxFe3−xO4 MNPs with a 0.5 nm Mn-ferrite shell. Mössbauer spectroscopy, x-ray absorption spectroscopy and x-ray magnetic circular dichroism are used to determine chemical structure of core and shell. Polarized small angle neutron scattering shows parallel and perpendicular magnetic correlations, suggesting multiparticle coherent spin canting in an applied field. Atomistic simulations reveal the underlying mechanism of the observed spin canting. These show that strong DMI can lead to magnetic frustration within the shell and cause canting of the net particle moment. These results illuminate how core/shell nanoparticle systems can be engineered for spin canting across the whole of the particle, rather than solely at the surface.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2018 |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 21 Feb 2018 14:30 |
Last Modified: | 16 Oct 2024 14:29 |
Published Version: | https://doi.org/10.1038/s41598-018-21626-0 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1038/s41598-018-21626-0 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:127825 |
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Description: Spin canting across core/shell Fe3O4/MnxFe3−xO4 nanoparticles
Licence: CC-BY 2.5