TY - JOUR
T1 - Visualizing magnetic structure in 3d nanoscale ni-fe gyroid networks
AU - Llandro, Justin
AU - Love, David M.
AU - Kovács, András
AU - Caron, Jan
AU - Vyas, Kunal N.
AU - Kákay, Attila
AU - Salikhov, Ruslan
AU - Lenz, Kilian
AU - Fassbender, Jürgen
AU - Scherer, Maik R.J.
AU - Cimorra, Christian
AU - Steiner, Ullrich
AU - Barnes, Crispin H.W.
AU - Dunin-Borkowski, Rafal E.
AU - Fukami, Shunsuke
AU - Ohno, Hideo
N1 - Funding Information:
J.L. thanks Tomasz Dietl for helpful discussions and acknowledges GP-Spin at Tohoku University for support and also postdoctoral funding from EPSRC Grant EP/J00412X/1 “Mapping Spin Polarisation in Quasi-One-Dimensional Channels”. This project has received funding from the European Research Council (ERC) under the Grant Agreement 320832, the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement 856538, and the Japan Society for the Promotion of Science (JSPS) under Kakenhi Grant No. 19H05622 and the Core-to-Core Program. M.R.J.S. acknowledges funding from Nokia Research Centre Cambridge. U.S. acknowledges funding from the Adolphe Merkle Foundation. J.L. and A.K. acknowledge Naëmi Leo for her helpful suggestions on the manuscript.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/5/13
Y1 - 2020/5/13
N2 - 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 Ni75Fe25 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.
AB - 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 Ni75Fe25 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.
KW - Gyroids
KW - Magnetic metamaterials
KW - Off-axis electron holography
KW - Transmission electron microscopy
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U2 - 10.1021/acs.nanolett.0c00578
DO - 10.1021/acs.nanolett.0c00578
M3 - Article
C2 - 32250635
AN - SCOPUS:85084692867
VL - 20
SP - 3642
EP - 3650
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 5
ER -