Abstract
Spin waves, the collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact. These solitons are expected to have essentially cylindrical symmetry (that is, s-like), but no direct experimental observation exists to confirm this picture. Using a high-sensitivity time-resolved magnetic X-ray microscopy with 50 ps temporal resolution and 35 nm spatial resolution, we are able to create a real-space spin-wave movie and observe the emergence of a localized soliton with a nodal line, that is, with p-like symmetry. Micromagnetic simulations explain the measurements and reveal that the symmetry of the soliton can be controlled by magnetic fields. Our results broaden the understanding of spin-wave dynamics at the nanoscale, with implications for the design of magnetic nanodevices.
Highlights
Spin waves, the collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact
For the case of localized excitations, created when an in-plane magnetic field is applied to the sample, the Oersted field does break the in-plane symmetry, and a spatial shift of the excitation away from the nano-contact has been predicted by numerical simulations[19,20,21]
Our results reveal the existence of a localized spin-wave soliton characterized by a nodal line
Summary
The collective excitations of spins, can emerge as nonlinear solitons at the nanoscale when excited by an electrical current from a nanocontact. It is established that the local injection of strong spinpolarized electrical currents can generate nonlinear spin waves with both itinerant[9,10,11,12,13] and localized[11,14,15,16,17,18] character This character is determined by the relative orientation between the material internal field and the applied external field. Spin waves of both characters are required to preserve the radial symmetry of the nanocontact used to inject the spin-polarized current Such radial symmetry can be perturbed by the Oersted field generated by the current flowing through the nano-contact, with qualitatively different effects for itinerant and localized excitations. Micromagnetic simulations reproduce this p-like soliton and demonstrate a transition to s-like symmetry with increasing confinement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
