Category: Papers
Pumping magnons with solitons
Congratulations to Medhanie who published his work on spin hydrodynamics on Phys. Rev. B 110, 174424 (2024). This work shows that a rather special solution called a contact soliton dissipative exchange flow can be modulated by spin injection, in turn pumping magnons into the ferromagnetic channel.
This work also extended our pseudospectral Landau-Lifshitz model with spin transfer torque and demonstrated the importance of correctly manage the exchange energy when solitons are present in the system due to their sharp domain walls.
Ferromagnetic resonance in 3D tilted ASI
Congratulations to Ghanem and Ally who published a joint paper in the semi-analytical and numerical investigation of 3D artificial spin ices. This work is the first to explore this challenging geometry from two numerical perspectives.
This work shows not only the advantages but also the issues that different models present when exploring 3D geometries.
3D spin ice published in Nature Communications
Our collaborative work on 3D artificial spin ices was just published on Nature Communications. The work combines very nice experimental work lead by Imperial College London as well as numerical simulations, Brillouin light scattering, and calculations using our in-house semi-analytical code Gænice.
We obtained very good agreement with experiments by combining our method to numerical estimate diagonalized demag factors and semi-analytical FMR calculations. This work demonstrated Gænice’s application to 3D spin ice geometries.
Pseudospectral method resolves atomic scale dynamics
We have published a new continuum method that resolves atomic-scale magnetization dynamics with good accuracy. The method is pseudospectral and so is amenable to analytical calculation. Limiting cases of modulational instability (a long-wave phenomenon) and transient grating (a regime where long and short waves co-exist) were resolved in excellent agreement with atomistic spin dynamics. We expect this model to be the foundational stone for a better modeling of topological textures.
Fantastic work by Kyle Rockwell on this research and special thanks to our international collaborators Joel Hirst and Thomas Ostler.
This research was supported by the U.S. Department of Energy, Office of Science.
Nano-magnonic crystals
Ally published her first-author investigation of magnonic band structure in nano-magnonic crystals. These are magnonic crystals with parameters modulated at the nanoscale which could leverage new techniques in material science with tens of nanometer resolution. Congratulations Ally!
The paper can be found at Magnetochemistry 10, 14 (2024)
Ultrafast domain-wall motion
We are very happy that our work on ultrafast magnetization dynamics has been published in Physical Review Letter as editors’ suggestion and featured in the Physics magazine. This collaborative work features experiments performed at FERMI free-electron laser in Italy. Based on the data, we were able to discern changes in the scattering and link them to curvature-dependent distortions in the domain pattern. Congratulations to all authors and special mention to Kyle’s work and contribution to this research!
The paper can be found in Phys. Rev. Lett. 131, 256702 (2023)
Published method for general ASI magnon band structure
Our work on Gænice has been published in J. Magn. Magn. Mater. 589, 171603 (2023). Very nice piece of work that will allow us to explore new artificial spin ice geometries with exciting magnonic functionalities.
The code is free to use and can be downloaded from our repository.
Numerical approach to approximate demag factors
Our method to determine demag factors for stadium-shaped nanoislands has been published in IEEE Magnetic Letters. This approach goes in tandem with Gænice to obtain a quantitative agreement with Kittel’s equation using the approximation of a diagonal demag tensor. The level of accuracy obtained allows us to resolve the resonant frequencies at low bias fields, as it is often the case in artificial spin ices.
Nonlinear magnon scattering in ASI
Experiments and simulations unveiled magnon scattering in ASIs due to nonlinear processes. These were only observed in continuous magnetic films but in our recent Nature Communications, we demonstrate that similar processes are allowed by the coupling between adjacent nanoislands in ASIs. Beautiful experiments done at M. B. Jungfliesch’s group!
Topological magnetic monopoles
The experimental identification of topological magnetic monopoles, or hedgehogs, was published in Nature Nanotechnology. Outstanding experiments performed at COSMIC allowing for an unprecedented 10 nm resolution in the 3D-reconstructed magnetization vector of a frustrated metalattice. We were able to determine the textures’ topology directly from experimental results, identifying both hedgehogs in the bulk of the materials and “virtual” hedgehogs whose topology is bound to the material’s surfaces. For more information, see the research highlight in the STROBE website.