Chiral Nanomagnets

Sahand Eslami, John G. Gibbs, Yvonne Rechkemmer, Joris Van Slageren, Mariana Alarcón-Correa, Tung Chun Lee, Andrew G. Mark, Geert L.J.A. Rikken, Peer Fischer

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

We report on the enhanced optical properties of chiral magnetic nanohelices with critical dimensions comparable to the ferromagnetic domain size. They are shown to be ferromagnetic at room temperature, have defined chirality, and exhibit large optical activity in the visible as verified by electron microscopy, superconducting quantum interference device (SQUID) magnetometry, natural circular dichroism (NCD), and magnetic circular dichroism (MCD) measurements. The structures exhibit magneto-chiral dichroism (MChD), which directly demonstrates coupling between their structural chirality and magnetism. A chiral nickel (Ni) film consisting of an array of nanohelices ∼100 nm in length exhibits an MChD anisotropy factor gMChD ≈ 10-4 T-1 at room temperature in a saturation field of ∼0.2 T, permitting polarization-independent control of the film's absorption properties through magnetic field modulation. This is also the first report of MChD in a material with structural chirality on the order of the wavelength of light, and therefore the Ni nanohelix array is a metamaterial with magnetochiral properties that can be tailored through a dynamic deposition process. (Figure Presented).

Original languageEnglish (US)
Pages (from-to)1231-1236
Number of pages6
JournalACS Photonics
Volume1
Issue number11
DOIs
StatePublished - Nov 19 2014

Keywords

  • chiral
  • circular dichroism
  • ferromagnetism
  • magnetochiral dichroism
  • nanohelix
  • nanomagnet

ASJC Scopus subject areas

  • Biotechnology
  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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