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G. Alatteili

Publications and source records attributed to G. Alatteili.

3 recordsLinked to original sources

GæniceN: a minimal model to relax magnetization states self-consistently in general artificial spin ices

Artificial spin ices are geometric arrangement of nanomagnets that exhibit reconfigurable magnetization states and GHz dynamics. Their investigation in the GHz regime is challenging because of the existence of multiple modes and the impact of magnetization deviations at the edges of the nanomagnets. A minimal model to capture such dynamics require three macrospins per nanomagnet, an approach that was implemented for generic artificial spin ices in the tool Gaenice. Here, we use the Gaenice framework to realize a relaxation method to stabilize magnetization states self-consistently, called GaeniceN. We implement the dissipative component of the Landau-Lifshitz equation in an iterative approach to efficiently converge to the relaxed state. As an example, we find our approach to correctly predict the transition between phases in a pyramid ASI subject to a low-magnitude external field by computing the system's average energy. Because they are rooted on the same framework, GaeniceN produces the initial condition needed for Gaenice to compute dynamics such as ferromagnetic resonance or band structures. Combined, these tools will be able to aid in the design of artificial spin ices with applications in magnonics.

cond-mat.mes-hall↗

Ferromagnetic resonance modes in trilayer artificial spin ices subject to interfacial Dzyaloshinskii-Moriya interaction

Artificial spin ices are metamaterials that can host several ferromagnetic resonances as well as spin waves. As the field advances towards the creation of three-dimensional geometries, a trilayer square artificial spin ice has been already found to exhibit many interesting properties. Here, we numerically investigate a strongly-coupled trialyer square artificial spin ice under the effect of interfacial Dzyaloshinskii-Moriya interaction (DMI). This interaction affords non-reciprocity to waves, leading to changes in the standing wave modes established in confined geometries. We find that the interplay between the non-reciprocity, an applied field, and the stray field within the artificial spin ice results in frequency split additional edge modes. The edge modes are favored by the DMI sign and exhibit destructive and constructive interference depending on both the DMI magnitude and the external magnetic field. Our results demonstrate the non-reciprocity in small nanoislands can affect the long-range states stabilized in the artificial spin ice due to the strong coupling between layers.

cond-mat.mes-hall↗

Symmetry-broken magneto-toroidal artificial spin ices: magnetization states and dynamics

Magneto-toroidal artificial spin ices (MT-ASIs) are arrangements of nanomagnets that exhibit spontaneous toroidization. A ferrotoroidic order could have implications on the propagation of spin waves through this artificial spin ice, including the development of topological edge modes. Here, we numerically investigate the magnetization dynamics of an MT-ASI with and without spatial symmetry breaking. Through micromagnetic simulations, we compute the energies and ferromagnetic resonance spectra of the four lowest-order states, which exhibit ferrotoroidicity, antiferrotoroidicity, and no toroidicity. As expected, we find that the resonant modes split when spatial symmetry is broken. To determine whether our system exhibits topologically protected edge modes, we perform semi-analytical calculations to first estimate the ferromagnetic resonance and then compute the band structure. Our results show that symmetry-broken MT-ASIs are reconfigurable by magnetic field protocols, and that their band structures depend on magnetization state. Calculation of the Chern number indicates that the bands are topologically trivial in all cases, suggesting that the dynamic magnetic coupling is weak. The absence of a non-zero Chern number is proof of the weak dynamic coupling in ASIs, which must be addressed to unlock their full potential in magnonics applications.

cond-mat.mes-hall↗