Comparison of conventional and Lorentz transmission electron microscopy in magnetic imaging of permanent magnets
Open access
Date
2021-07-12Type
- Journal Article
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yes
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Abstract
Magnetization structures in magnetic materials are usually imaged in dedicated Lorentz transmission electron microscopes. Compared to conventional transmission electron microscopes, the magnetic field of the objective lens at the sample is removed by replacing the objective lens with a Lorentz lens below the sample. While this modification is critical for soft-magnetic materials whose magnetic state is affected by the strong magnetic field of the objective lens, we propose that this is not necessary for permanent magnets such as Sm-Co and Nd-Fe-B. Conventional and Lorentz microscopes are compared for imaging divergent and convergent domain walls in a Sm(Co,Fe,Cu,Zr)(7.7) magnet. Both techniques provide an almost identical resolution and accuracy in the measurement of the domain-wall width parameter using focal-series imaging of divergent domain walls. It is further demonstrated that both techniques can be utilized to analyze the intensity profile of convergent domain walls. From this, the product of sample thickness and magnetic induction is extracted. These results illustrate that conventional microscopes can be used to image the magnetic state of permanent magnets with a resolution comparable to dedicated Lorentz microscopes, which make magnetic imaging experiments significantly more accessible to a wider scientific community. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000496953Publication status
publishedExternal links
Journal / series
Applied Physics LettersVolume
Pages / Article No.
Publisher
American Institute of PhysicsOrganisational unit
03661 - Löffler, Jörg F. / Löffler, Jörg F.
02891 - ScopeM / ScopeM
Funding
172934 - Advanced nanoscale characterization of magnetic defects in metals (SNF)
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ETH Bibliography
yes
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