Oral presentation

Session Information

Location: Science and Cultural Center - FORTH
Day: 2. Thursday 17th
Time: 15:50-16:10
Chairperson: to be announced…

Presentation Details

Presentation Type: Oral presentation
Title: Dynamic Fingerprinting of Topological Nucleation in Bilayer Synthetic Antiferromagnets
Abstract:  The stability of topological spin textures, such as magnetic skyrmions, in two-dimensional van der Waals heterostructures and their behavior under dynamic magnetic fields form the foundation of next-generation, high-density spintronic devices. In this context, synthetic antiferromagnetic (SAF) bilayers are of paramount technological importance; the exact cancellation of macroscopic magnetization in SAFs not only minimizes stray fields for denser packing but also strictly suppresses the detrimental skyrmion Hall effect, ensuring purely longitudinal, ultrafast topological motion. Furthermore, the specific dynamic responses of these textures (e.g., breathing and gyration modes) find direct applications in magnetically tunable microwave filters, spin-torque nano-oscillators, and energy-efficient neuromorphic computing architectures. In this study, the thermodynamic ground states of a bilayer chiral SAF are rigorously investigated using Landau-Lifshitz-Gilbert (LLG) atomistic spin dynamics simulations. We objectively explore the role of Dzyaloshinskii-Moriya interaction ($D$), perpendicular magnetic anisotropy, out-of-plane magnetic field , and interlayer antiferromagnetic exchange coupling on topological stability. To model the dynamic response and characterize topological phase transitions via a time-dependent Gaussian magnetic field pulse is applied to the relaxed ground states. Focusing on critical regimes where interlayer exchange interaction actively drives topological nucleation, the transient magnetization dynamics are analyzed via Fast Fourier Transform. This approach systematically isolates the resonance spectra of dominant spin-wave excitations, such as the high-frequency breathing mode. The study aims to demonstrate that interlayer exchange interaction is not merely a destructive factor that strictly tears the system into trivial labyrinth phases; rather, within an optimal parameter window, it acts as a catalyst that stabilizes the Skyrmion Crystal (SkX) phase. Under the high-anisotropy regime, the geometric frustration between intralayer chirality and interlayer anti-alignment drastically lowers the nucleation barrier—facilitating a direct transition from a collinear field-polarized state to a Skyrmion Gas (SkG). This transition is anticipated to be confirmed by distinct frequency shifts (mode softening) in the extracted resonance spectra. These dynamic findings will provide a definitive, non-destructive criterion to explicitly distinguish topological phases from trivial collinear states, offering fundamental physical principles for the design of robust topological magnonic devices.

Presenter

Dr Ümit Akıncı
Dokuz Eylül University | Türkiye

Authors

1. Akıncı, Ümit | Department of Physics, Dokuz Eylül University, TR-35160 Izmir, Turkey