Spin wave propagation properties across configurational antiferro/ferro-magnetic transitions

Abstract

The purpose of this numerical study, performed within the micromagnetic framework and the dynamical matrix method, is to understand how the propagation of spin waves in a macrospin chain is affected by a configurational rearrangement of the magnetization, induced by a progressive variation of a magnetic field. Our macrospins are modelized through thin cylinders with elliptical cross sections that display a monodomain, bistable magnetization distribution; hence, the allowed magnetization configurations of the chain are either antiferromagnetic (AF) or ferromagnetic (FM). We illustrate the peculiar features of spin waves in the AF and FM configurations concerning the dispersion relations, phase amplitude variations and localization, and precession ellipticity, as a function of the applied field, particularly close to the critical field values at which the configurational rearrangements occur (AF-to-FM or vice versa). A remarkable effect that arises on the mode frequency and bandwidth across a configurational transition is the frequency invariance of specific Bloch waves, particularly attractive for processing the spin wave signals in low dissipation magnon-spintronic devices.

A Brillouin light scattering study of the spin-wave magnetic field dependence in a magnetic hybrid system made of an artificial spin-ice structure and a film underlayer

“…In the ideal case, this mode should not have any (or only a small) discontinuity in crossing the field line II, where the reversal of the vertical island occurs (see Ref. [33]); 2.) the curve associated with peak (1) continues to decrease even after line IV (i.e., above zero field) down to the transition point line II.…”

Ferromagnetic resonance spectra of permalloy nano-ellipses as building blocks for complex magnonic lattices

“…3(h)], that is assigned to a soft mode. 8,20 The red solid lines in Fig. 3 show the results of the theoretical calculations for the nanoellipses with different angles corresponding to the experimental data, when the applied d.c. magnetic field lies along the CPW axis, i.e.…”

Influence of the Vertex Region on Spin Dynamics in Artificial Kagome Spin Ice

“…In order to corroborate the localized nature of the VCM, we used the analytical formula for a fundamental Kittel mode 27,28 with frequency f = ω/2π and:…”