Tuning the Magneto-Optical Response of Nanosize Ferromagnetic Ni Disks Using the Phase of Localized Plasmons

Abstract

We explore the influence of the phase of localized plasmon resonances on the magneto-optical activity of nanoferromagnets. We demonstrate that these systems can be described as two orthogonal damped oscillators coupled by the spin-orbit interaction. We prove that only the spin-orbit induced transverse plasmon plays an active role on the magneto-optical properties by controlling the relative amplitude and phase lag between the two oscillators. Our theoretical predictions are fully confirmed by magneto-optical Kerr effect and optical extinction measurements in nanostructures of different size and shape.

Hybrid Ni/SiO2/Au dimer arrays for high-resolution refractive index sensing

“…If the magnetization in Ni is oriented perpendicular to the disk by an external magnetic field, an orthogonal electric dipole is also excited along the y axis because of spin-orbit interactions (d y-Ni ). The magnitude of this so-called magneto-optical dipole is typically 100-500 times smaller than the electric dipole along the x axis [13]. Finally, near-field coupling between the Ni and Au nanodisks induces an orthogonal electric dipole in Au (d y-Au ).…”

“…In ferromagnetic nanoparticles, spin-orbit coupling results in the excitation of two LSPRs, one along the direction of the incident electric field and the second induced orthogonally to the first and the direction of magnetization [13]. The amplitude and phase relations of these two LSPRs determine the magneto-optical response of a ferromagnetic nanoparticle, i.e.…”

Plasmonic nanodevice with magnetic funcionalities: fabrication and characterization

“…Hence, it is difficult to achieve ferromagnetic and plasmonic behaviors in the same material. Only recently, nanostructures of Ni [14][15][16][17][18][19][20] Ni/Co [21] and permalloy antidots [22] have been reported to exhibit surface plasmons in combination with their well-known ferromagnetic character at room temperature. However, the intensity of the plasmonic resonance in these type of materials is fairly weaker than for noble metals as Au or Ag where the electromagnetic field can be increased locally up to 80 times upon excitation of surface plasmons [23].…”

Enhanced Magneto-Optical Edge Excitation in Nanoscale Magnetic Disks

“…The vast majority of studies in this field has been performed on nonmagnetic metallic nanostructures and focused primarily on localized surface plasmon resonances [12]. Nanostructures using magneto-optically active materials, such as metallic ferromagnets, started to attract attention only recently, leading to the rapidly developing field of magnetoplasmonics, which combines concepts of plasmonics and magnetism for the purpose of unveiling novel phenomena and functionalities at the nanoscale [13][14][15][16][17][18][19][20][21][22][23][24]. Key findings are hereby the ability to magnetically influence plasmonic properties and in return influence magneto-optical effects via plasmon resonances.…”