Optically Induced Tunable Magnetization Dynamics in Nanoscale Co Antidot Lattices

Abstract

We report the time-domain measurements of optically induced precessional dynamics in a series of Co antidot lattices with fixed antidot diameter of 100 nm and with varying lattice constants (S) between 200 and 500 nm. For the sparsest lattice, we observe two bands of precessional modes with a band gap, which increases substantially with the decrease in S down to 300 nm. At S = 200 nm, four distinct bands with significant band gaps appear. The numerically calculated mode profiles show various localized and extended modes with the propagation direction perpendicular to the bias magnetic field. We numerically demonstrate some composite antidot structures with very rich magnonic spectra spreading between 3 and 27 GHz based upon the above experimental observation.

Effect of hole shape on spin-wave band structure in one-dimensional magnonic antidot waveguide

“…Magnetic antidots have emerged as an important system of MCs; and a thorough investigation of high frequency magnetization dynamics in them has been reported in the literature. [30][31][32][33][34][35] Magnonic antidot waveguide (MAW) is an attractive option for manipulation of transmitted spin waves towards the above application, but it has only recently been started to be explored. [36][37][38] So far, a study of the dependence of spinwave dispersion on the shapes of the antidots has not been reported.…”

Control of spin-wave excitations in deterministic fractals

“…2(b) and 5(c). The mode profile is related to that of antidot arrays [17,47] and square nanorings [48]. No stable magnetization configuration was obtained in the simulations between −10 mT and 7 mT.…”

Magnonic Crystals

“…These two assumptions are fulfilled to a large extent in many recent experimental studies of thin-film MCs. (30)(31)(32)(33)(34)(35)(36) As compared to the parabolic and linear dispersion relations of electronic and electromagnetic waves, respectively, in homogeneous media, the SW dispersion relation f (k) described by equation 13 has a complex and nonmonotonic dependence on the in-plane wave vector. The SW frequency depends on (i) the wavenumber k, (ii) the magnitude of the external magnetic field H 0 , and (iii) its orientation with respect to k and the film plane (angles ϕ and ϑ); apart from these, (iv) the magnetocrystalline anisotropy and (v) 1 The static effective field defines the equilibrium orientation of the magnetization and can be calculated by minimization of the self-energy, usually composed of a demagnetizing term (see Sec.…”