Direct mapping of spin wave modes of individual Ni₈₀Fe₂₀ nanorings

Abstract

Ferromagnetic nanorings exhibit tunable magnetic states with unique magnetization reversal processes and dynamic behavior that can be exploited in data storage and magnonic devices. Traditionally, probing the magnetization dynamics of individual ferromagnetic nanorings and mapping the resonance modes has proved challenging. In this study, micro-focused Brillouin light scattering spectroscopy is used to directly map the spin wave modes and their intensities in nanorings as a function of ring width and applied magnetic field. Micromagnetic simulations provide further insights into the experimental observations and are in good agreement with the experimental results. These results can help in improving the understanding of spin wave confinement in single elements for magnonic devices and waveguides.

Spin waves in unsaturated single- and double-layered ferromagnetic nanorings

“…We presented calculations for both the frequencies and the position-dependent amplitudes of the SW modes. The amplitudes (or the corresponding intensities) and frequencies can be studied experimentally by micro-focused BLS, as demonstrated recently by [21] for large-diameter single-layered Py nanorings.…”

“…Presently magnetization and magnetoresistance studies have been conducted for several basic geometries, such as on disks and/or rings with either square, rectangular, circular, or elliptical shapes [4,[9][10][11][12][13][14][15][16], as well as cylindrical nanorods and nanotubes [17,18]. Among these, particular attention, both theoretical and experimental, has been directed towards circular nanorings that have a thickness much less than the inner and outer radii [17,[19][20][21][22][23][24][25]. In part, this is because their circular symmetry is advantageous for technological applications due to their fundamental properties and potential for highfrequency switching and storage devices [4,6].…”

“…Also the resonant SWs in Py nanorings were studied using microwave absorption by [28,31]. Very recently [21] used micro-focused BLS to study both the frequencies and intensities of the SWs in a Py nanoring for the VS and OS regions.…”

Effect of nonuniform perpendicular anisotropy in ferromagnetic resonance spectra in magnetic nanorings

“…Micromagnetic simulations where used in order to study the FMR spectra of these kind of magnetic nanostructures, by solving the Landau Lifshitz Gilbert (LLG) equation and using the Ringdown method 18 – 20 to obtain the dynamic response of the system. It is worthwhile to mention that dynamical susceptibility using micromagnetic simulations in ring shaped nanostructures was previously extensively studied 21 – 24 , showing the interest of the scientific community in this topic. Up today, there are no studies about the dynamic response of these geometries when a nonuniform perpendicular anisotropy is included, which is very interesting due to the knot configuration offer a non symmetric configuration of the magnetization which offer more control parameters for the dynamic response, and the meron configuration contains an out-of-plane component of the magnetization thats allows to appear new resonant modes.…”

Engineering spin wave spectra in thick Ni80Fe20 rings by using competition between exchange and dipolar fields

“…The discovery of fascinating properties of ferromagnetic rings (vortex and onion magnetic states below saturation, specific features of the switching behavior, and peculiarities of magnetic dynamics) [16][17][18][19][20][21] as well as the possibility to control vortex chirality in rings [22,23] make them a promising candidate for usage in magnetoresistive random access memory (MRAM) devices [24,25] and logic circuits [26]. Very recently nanovolcanoes-nanodisks overlaid by nanoringswere proposed as purpose-engineered three-dimensional (3D) architectures for nanomagnonics [27].…”