Self-Assembled Magnetic Nanoparticle Layers: Structural Control for Reconfigurable Magnetism and Functional Applications
We advance soft X-ray vector ptychographic tomography to map the 3D magnetization field in self-assembled superparamagnetic nanoparticles at a liquid–liquid interface, revealing how layered structures influence magnetic ordering. We observe that monolayers with low coordination numbers exhibit weak magnetic order, with magnetic vortices disrupting spin alignment. In contrast, bilayers and trilayers with higher coordination numbers display long-range magnetic order with strong spin correlations across larger distances and a suppression of magnetic vortices. We further quantify the average distance for vortex–antivortex pairs as 26.0 ± 2.0 nm, while vortex–vortex and antivortex–antivortex pairs exhibit larger separations, averaging 44.9 ± 5.2 and 54.1 ± 7.4 nm, respectively. These experimental results are supported by micromagnetic Monte Carlo simulations. Our findings illustrate how layered structures enhance magnetic order and spin correlation in superparamagnetic nanoparticle assemblies, providing a promising approach for tuning magnetic properties in applications such as data storage, microrobotics, and biomedicine.
Authors
- Xingyuan Lu (ORCID: https://orcid.org/0000-0001-9756-8767)
- Ji Zou (ORCID: https://orcid.org/0000-0003-0828-1153)
- Jianwei Miao (ORCID: https://orcid.org/0000-0003-4033-3945)
- Robert Streubel (ORCID: https://orcid.org/0000-0003-4783-892X)
- Henry C. Kapteyn (ORCID: https://orcid.org/0000-0001-8386-6317)
- Yaroslav Tserkovnyak (ORCID: https://orcid.org/0000-0002-3277-3695)
- Thomas P. Russell (ORCID: https://orcid.org/0000-0001-6384-5826)
- Minh Phạm (ORCID: https://orcid.org/0000-0002-5019-6449)
- Charles S. Bevis (ORCID: https://orcid.org/0000-0002-8671-0681)
- Robert Karl (ORCID: https://orcid.org/0000-0002-2955-5507)
- Chen-Ting Liao (ORCID: https://orcid.org/0000-0002-3423-277X)
- Yuan Hung Lo (ORCID: https://orcid.org/0000-0002-2135-935X)
- Serban Lepadatu (ORCID: https://orcid.org/0000-0001-6221-9727)
- Д. А. Шапиро (ORCID: https://orcid.org/0000-0003-1116-7298)
- Xuefei Wu (ORCID: https://orcid.org/0000-0001-9435-4384)
- Margaret M. Murnane (ORCID: https://orcid.org/0000-0001-9689-5432)
- Young-Sang Yu
- Arjun Rana
- Emma Cating Subramanian
Institutions
- University of Nebraska–Lincoln (US)
- Statewide California Earthquake Center (US)
- Joint Institute for Laboratory Astrophysics (US)
- California NanoSystems Institute (US)
- Lawrence Berkeley National Laboratory (US)
- University of Basel (CH)
- University of California System (US)
- Advanced Light Source
- Toronto Metropolitan University (CA)
Publication Details
- Journal
- ACS Applied Nano Materials
- Published
- 2025-03-20
- DOI
- https://doi.org/10.1021/acsanm.5c00461
- Primary Topic
- Magnetic properties of thin films
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Multidisciplinary University Research Initiative
- Division of Materials Research
- Basic Energy Sciences