Tunable Angle-Dependent Magnetization Dynamics in Ni80Fe20 Nanocross Structures of Varying Size

Abstract

We demonstrate a large angular dependence of magnetization dynamics in Ni 80 Fe 20 nanocross arrays of varying sizes. By subtle variation of the azimuthal angle (φ) of an in-plane bias magnetic field, the spin configuration and the ensuing spin-wave dynamics, including mode softening, mode splitting, mode crossover and mode merging, can be drastically varied to the extent that a frequency minimum corresponding to mode softening converts to a mode crossover, various mode splitting and mode crossover disappear and additional mode splitting appears. Numerically simulated spin-wave spectra and phase profiles revealed the nature of various spin-wave modes and the origin of above variation of the dynamics with bias-field angle. All of these above observations are further modified with the variation of dimensions of the nano-cross. The numerically calculated magnetostatic field distributions further supports the variation of dynamics with bias-field angle. Theseresults open a new avenue for engineering the nano-cross based magnetic devices such as magnetic storage, spin-wave logic and on-chip data communication devices.

Magnetization dynamics of nanoscale magnetic materials: A perspective

“…The values of the effective demagnetization factors have been extracted from the collective modes as shown in the figure caption. The cross-shaped element continues to show great prospects with observations like mode softening, mode crossover, mode splitting and merging of SW frequency branches with the bias field strength and orientation 109 and more recently a strong magnon-magnon coupling and nonlinear FMR behaviour 110 .…”

Linear chains of nanomagnets: engineering the effective magnetic anisotropy

“…Magnetic nanostructures have been extensively studied in various systems for example in magnetic dots with negligible shape anisotropy, [18,19] nanowires incorporating strong shape anisotropy, [20,21] rectangular dots/antidots/ring/mutually-crossed nanomagnets, [22][23][24][25] reconfigurable magnonic crystal with rhomboid-shaped nanomagnets for deterministic control of magnetization dynamics, [26,27] magnetic quantum cellular automata (MQCA) based devices [28,29] and artificial spin ice nanostructures. [30][31][32] In this paper, we demonstrate the control of effective magnetic anisotropy in linear chains of NMs by tuning the configurational anisotropy, thickness, and applied field directions.…”

The effect of material defects on resonant spin wave modes in a nanomagnet

“…Later, interest shifted towards understanding the collective dynamics in an array of nanomagnets 12,13 , which emerged as a potential candidate for a two-dimensional magnonic crystal. Much work has been reported on the dependence of spin wave dynamics on the size and the shape of nanomagnets, the lattice constant, the lattice symmetry of the array, bias field strength and orientation, as well as binary and bi-component nature [14][15][16][17][18][19][20] . Important physical phenomena such as spin wave mode splitting, mode cross-over, dynamic dephasing, transition between various collective regimes, intrinsic and extrinsic dynamical configurational anisotropy, etc.…”