%0 Journal Article
%A Llandro, Justin
%A Love, David M.
%A Kovács, András
%A Caron, Jan
%A Vyas, Kunal N.
%A Kákay, Attila
%A Salikhov, Ruslan
%A Lenz, Kilian
%A Fassbender, Jürgen
%A Scherer, Maik R. J.
%A Cimorra, Christian
%A Steiner, Ullrich
%A Barnes, Crispin H. W.
%A Dunin-Borkowski, Rafal E.
%A Fukami, Shunsuke
%A Ohno, Hideo
%T Visualizing Magnetic Structure in 3D Nanoscale Ni–Fe Gyroid Networks
%J Nano letters
%V 20
%N 5
%@ 1530-6992
%C Washington, DC
%I ACS Publ.
%M FZJ-2020-02732
%P 3642 - 3650
%D 2020
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:32250635
%U <Go to ISI:>//WOS:000535255300092
%R 10.1021/acs.nanolett.0c00578
%U https://juser.fz-juelich.de/record/878263