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Visualizing Magnetic Structure in 3D Nanoscale Ni-Fe Gyroid Networks.
- Source :
-
Nano letters [Nano Lett] 2020 May 13; Vol. 20 (5), pp. 3642-3650. Date of Electronic Publication: 2020 Apr 10. - Publication Year :
- 2020
-
Abstract
- Arrays of interacting 2D nanomagnets display unprecedented electromagnetic properties via collective effects, demonstrated in artificial spin ices and magnonic crystals. Progress toward 3D magnetic metamaterials is hampered by two challenges: fabricating 3D structures near intrinsic magnetic length scales (sub-100 nm) and visualizing their magnetic configurations. Here, we fabricate and measure nanoscale magnetic gyroids, periodic chiral networks comprising nanowire-like struts forming three-connected vertices. Via block copolymer templating, we produce Ni <subscript>75</subscript> Fe <subscript>25</subscript> single-gyroid and double-gyroid (an inversion pair of single-gyroids) nanostructures with a 42 nm unit cell and 11 nm diameter struts, comparable to the exchange length in Ni-Fe. We visualize their magnetization distributions via off-axis electron holography with nanometer spatial resolution and interpret the patterns using finite-element micromagnetic simulations. Our results suggest an intricate, frustrated remanent state which is ferromagnetic but without a unique equilibrium configuration, opening new possibilities for collective phenomena in magnetism, including 3D magnonic crystals and unconventional computing.
Details
- Language :
- English
- ISSN :
- 1530-6992
- Volume :
- 20
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Nano letters
- Publication Type :
- Academic Journal
- Accession number :
- 32250635
- Full Text :
- https://doi.org/10.1021/acs.nanolett.0c00578