Non-equilibrium self-assembly of spin-wave solitons in FePt nanoparticles Article Swipe

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Condensed matter physics Superparamagnetism Spin wave Soliton Precession Micromagnetics Spin (aerodynamics) Materials science Femtosecond Excitation Ferromagnetism Nanoparticle Physics Nanotechnology Laser Optics Magnetization Magnetic field Quantum mechanics Thermodynamics Nonlinear system

Diego Turenne , Alexander Yaroslavtsev , Xijie Wang , Vivek Unikandanuni , Igor Vaskivskyi , Michael Schneider , Emmanuelle Jal , Robert Carley , Giuseppe Mercurio , Rafael Gort , Naman Agarwal , Benjamin Van Kuiken , Laurent Mercadier , J. Schlappa , Loïc Le Guyader , Natalia Gerasimova , Martin Teichmann , D. Lomidze , A. Castoldi , Dmitrii V. Potorochin , Deepak John Mukkattukavil , Jeffrey A. Brock , Nanna Zhou Hagström , Alexander H. Reid , Xiaozhe Shen , Xijie Wang , Pablo Maldonado , Y. O. Kvashnin , Karel Carva , J. Wang , Y. K. Takahashi , Eric E. Fullerton , Stefan Eisebitt , P. M. Oppeneer , С. Л. Молодцов , Andreas Scherz , Stefano Bonetti , Ezio Iacocca , H. A. Dürr ·

YOU? · · 2021 · Open Access · · DOI: https://doi.org/10.48550/arxiv.2111.01649 · OA: W3210015409

Magnetic nanoparticles such as FePt in the L10-phase are the bedrock of our current data storage technology. As the grains become smaller to keep up with technological demands, the superparamagnetic limit calls for materials with higher magneto-crystalline anisotropy. This in turn reduces the magnetic exchange length to just a few nanometers enabling magnetic structures to be induced within the nanoparticles. Here we describe the existence of spin-wave solitons, dynamic localized bound states of spin-wave excitations, in FePt nanoparticles. We show with time-resolved X-ray diffraction and micromagnetic modeling that spin-wave solitons of sub-10 nm sizes form out of the demagnetized state following femtosecond laser excitation. The measured soliton spin-precession frequency of 0.1 THz positions this system as a platform to develop miniature devices capable of filling the THz gap.