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Title: Ferroplasmons: Intense Localized Surface Plasmons in Metal-Ferromagnetic Nanoparticles

Interaction of photons with matter at length scales far below their wavelengths has given rise to many novel phenomena, including localized surface plasmon resonance (LSPR). However, LSPR with narrow bandwidth (BW) is observed only in a select few noble metals, and ferromagnets are not among them. Here, we report the discovery of LSPR in ferromagnetic Co and CoFe alloy (8% Fe) in contact with Ag in the form of bimetallic nanoparticles prepared by pulsed laser dewetting. These plasmons in metal-erromagnetic nanostructures, or ferroplasmons (FP) for short, are in the visible spectrum with comparable intensity and BW to those of the LSPRs from the Ag regions. This finding was enabled by electron energy-loss mapping across individual nanoparticles in a monochromated scanning transmission electron microscope. The appearance of the FP is likely due to plasmonic interaction between the contacting Ag and Co nanoparticles. Since there is no previous evidence for materials that simultaneously show ferromagnetism and such intense LSPRs, this discovery may lead to the design of improved plasmonic materials and applications. It also demonstrates that materials with interesting plasmonic properties can be synthesized using bimetallic nanostructures in contact with each other.
 [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [4] ;  [5] ;  [2] ;  [1]
  1. University of Tennessee, Knoxville (UTK)
  2. ORNL
  3. Materials Science and Engineering Department, University of Tennessee, Knoxville, TN, USA
  4. Washington University, St. Louis
  5. Southern Illinois University
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Nano
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
localized surface plasmon resonance . electron energy-loss spectroscopy . bimetallic nanoparticles . hybridization . silver . scanning transmission electron microscopy . ferromagnet