Ferroplasmons: Intense Localized Surface Plasmons in Metal-Ferromagnetic Nanoparticles

Journal Article · Wed Jan 01 04:00:00 EST 2014 · ACS Nano

DOI:https://doi.org/10.1021/nn5031719· OSTI ID:1162085

Sachan, Ritesh ^[1]; Malasi, Abhinav ^[2]; Ge, Jingxuan ^[3]; Yadavali, Sagar P ^[2]; Gangopadhyay, Anup ^[4]; Krishna, Dr. Hare ^[4]; Garcia, Hernando ^[5]; Duscher, Gerd J M ^[2]; Kalyanaraman, Ramki ^[1]

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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

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.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1162085
• Journal Information: ACS Nano, Journal Name: ACS Nano
• Country of Publication: United States
• Language: English

Related Subjects

localized surface plasmon resonance . electron energy-loss spectroscopy . bimetallic nanoparticles . hybridization . silver . scanning transmission electron microscopy . ferromagnet