Tuning the Magneto-Optical Response of Nanosize Ferromagnetic Ni Disks Using the Phase of Localized Plasmons
CFM Seminars
- Speaker
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Paolo Vavassori (CIC nanoGUNE)
- When
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2014/03/19
13:00 - Place
- Auditorium of the Centro de Fisica de Materiales, Paseo Manuel de Lardizabal 5, Donostia-San Sebastián
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**Tuning the Magneto-Optical Response of Nanosize Ferromagnetic Ni Disks
Using** **the Phase of Localized Plasmons**
_P. Vavassori*_ 1,2 _, N. Maccaferri_ 1 _, V. Bonanni_ 3 _, S. Bonetti_ 4 _,
Z. Pirzadeh_ 5 _,_ _A. Dmitriev_ 5 _, K. Lodewijks_ 5 _,_ _J. Nogués_ 6 _, M.
Kataja_ 7 _, S._ _Van Dijken_ 7 _, and J. Akerman_ 8 __
(1) CIC Nanogune, San Sebastian, Spain
(2) Ikerbasque, Basque Foundation for Science, Bilbao, Spain
(3) CNR-ISTM and INSTM, 20133 Milano, Italy
(4) Department of Physics, Stanford University and Stanford Institute for
Materials and Energy Science (SIMES), SLAC National Accelerator Laboratory, CA
94305–2004 Stanford, U.S.A.
(5) Applied Physics, Chalmers University of Technology, Göteborg, Sweden
(6) ICREA and Catalan Institute of Nanotechnology, Bellaterra, Spain
(7) Applied Physics, Aalto University, Espoo, Finland
(8) Materials Physics, Royal Institute of Technology, Kista, Sweden
*E-mail: p.vavassori@nanogune.eu
Magneto-plasmonics materials combine magnetic and plasmonic functionalities
and are an emerging field of intense research as they would allow the design
of a new class of magnetically controllable optical nano-devices. Magneto-
plasmonics studies have mainly focused on hybrid multilayered structures
consisting of noble metals and ferromagnetic materials, where the noble metal
increases the plasmon response of the ferromagnetic material. Plasmon
properties of pure ferromagnetic nanostructures are a widely unexplored
terrain, although they offer the advantage of stronger magnetic polarization
and less demanding fabrication. Here we explore the opportunities arising from
direct excitation of localized surface plasmons (LSPs) in purely ferromagnetic
nanostructures due to the intertwined optical and magneto-optical properties.
We first show, using optical near-field microscopy and far-field spectroscopy,
that pure ferromagnetic nanostructures support LSP resonances as predicted by
theory [1]. A special feature of the ferromagnetic nanostructures is that the
near and far-field spectra are strongly shifted against each other, which can
be assigned to the their higher plasmon damping, when compared to noble
metals.
We then investigate the spectral magneto-optical (MO) response of such
nanostructures using different Kerr effect configurations [2-4]. We extended
present theoretical models based on generalized ellipsoidal nanoparticles in
order to account for both plasmonic and MO effects [4]. Guided by these
experimental findings and the results of our modeling efforts, we combine the
excitation of LSPs together with polarizability anisotropy to tune the phase
difference between the optical and MO induced polarizabilities beyond what is
offered by constituent material intrinsic properties and to manipulate the
reflected light’s polarization [3].
Such magneto-plasmonic nanostructures could be a building block for future
biotechnological and optoelectronic applications In particular we show that
magnetoplasmonic nanoparticles based detection schemes allow for unprecedented
sensitive detection.
**_References_**
[1] J. Chen et al., _Small_ **7** , 2341 (2011)
[2] V. Bonanni et al., _Nano Lett._ **11** , 5333 (2011)
[3] N. Maccaferri et al., _Phys. Rev. Lett._ **111** , 5333 (2013)
[4] K. Lodewijks et al., submitted to _Nano Lett._
[5] N. Maccaferri et al., _Opt. Express_ **21** , 9875 (2013)
[6] N. Maccaferri et al., submitted to _Physica Status Solidi_
[7] N. Maccaferri et al., in preparation.