Visualizing magnetic structure in 3d nanoscale ni-fe gyroid networks

Justin Llandro, David M. Love, András Kovács, Jan Caron, Kunal N. Vyas, Attila Kákay, Ruslan Salikhov, Kilian Lenz, Jürgen Fassbender, Maik R.J. Scherer, Christian Cimorra, Ullrich Steiner, Crispin H.W. Barnes, Rafal E. Dunin-Borkowski, Shunsuke Fukami, Hideo Ohno

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

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 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.

Original languageEnglish
Pages (from-to)3642-3650
Number of pages9
JournalNano Letters
Volume20
Issue number5
DOIs
Publication statusPublished - 2020 May 13

Keywords

  • Gyroids
  • Magnetic metamaterials
  • Off-axis electron holography
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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