Extending Field Limits in Nanoscale Magnetic Imaging with Metamaterial-inspired Magnetic Flux Concentrators

[en] Many nanoscale magnetic imaging techniques are constrained by the maximum magnetic field that can be applied during measurements, due to geometrical limitations or interactions with the probe or the detected signal (e.g., electrons). Here, it is demonstrated that sample-integrated metamaterial-inspired magnetic flux concentrators (MFCs) locally amplify magnetic fields, allowing observation of magnetization processes beyond instrumental limits. Micrometer-sized MFCs fabricated directly on the samples are tested in photoemission electron microscopy experiments employing X-ray magnetic circular dichroism as magnetic contrast mechanism. At low applied fields, substantial amplification factors enable observation of magnetization reversal in a chain of magnetite nanoparticles synthesized by magnetotactic bacteria at an applied field of 8 mT, substantially smaller than the 50 mT predicted by simulations in absence of MFCs. At higher fields, the field enhancement extends the accessible field range by a factor of five, enabling for the first time, imaging of the field-dependent magnetic domain structure evolution of an isolated giant magnetofossil. Finally, we show how MFC geometry and material parameters can be tuned to optimize performance considering sample and experimental constraints, providing a tunable and broadly applicable strategy for extending the accessible field range in a wide variety of nanoscale magnetic imaging techniques.

Disciplines :

Physics

Author, co-author :

Barrera, Aleix ; Institut De Ciència de Materials de Barcelona ICMAB‐CSIC Campus UAB Bellaterra Spain

Fourneau, Emile ; Université de Liège - ULiège > Département de physique > Physique expérimentale des matériaux nanostructurés

Pirottin, Thomas ; Université de Liège - ULiège > Département d'électricité, électronique et informatique (Institut Montefiore) > Electronique et microsystèmes

Marcano, Lourdes ; Departamento De Física Universidad De Oviedo Oviedo Spain

Abrudan, Radu ; Department of Spin and Topology in Quantum Materials Helmholtz‐Zentrum Berlin für Materialien und Energie Berlin Germany

Huang, Rong; Peking University Beijing China

Balcells, Ll. ; Institut De Ciència de Materials de Barcelona ICMAB‐CSIC Campus UAB Bellaterra Spain

Orue, Iñaki; SGIker Universidad Del País Vasco – UPV/EHU Leioa Spain

Fdez-Gubieda, Maria‐Luisa ; Dpto. Electricidad y Electrónica Universidad Del País Vasco – UPV/EHU Leioa Spain

Villanueva, Danny ; Dpto. Electricidad y Electrónica Universidad Del País Vasco – UPV/EHU Leioa Spain

More authors (7 more)

Language :

English

Title :

Extending Field Limits in Nanoscale Magnetic Imaging with Metamaterial-inspired Magnetic Flux Concentrators

Publication date :

2026

Journal title :

Small

ISSN :

1613-6810

eISSN :

1613-6829

Publisher :

Wiley

Peer reviewed :

Peer Reviewed verified by ORBi

Additional URL :

https://onlinelibrary.wiley.com/doi/pdf/10.1002/smll.202600073

Funders :

NSCF - National Natural Science Foundation of China
AEI - Agencia Estatal de Investigación

Commentary :

Submitted and accepted manuscript versions for Small (Wiley). To be published (Article DOI: 10.1002/smll.202600073)

Available on ORBi :

since 30 June 2026

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