2013/11/02 by Sang-Koog Kim, Sang‐Koog Kim, Kim, Sang-Koog +17
Engineering · Medicine · Physics and Astronomy · #Advanced Neuroimaging Techniques and Applications #Characterization and Applications of Magnetic Nanoparticles #FOS: Physical sciences #Magnetic properties of thin films #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #cond-mat.mes-hall
paper · pdf · doi:10.48550/arxiv.1311.0346
23 pages, 6 figures
openalex publication_date 2013/11/02 · arxiv created 2015/03/03 · arxiv updated 2015/03/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We found resonantly excited precession motions of a three-dimensional vortex core in soft magnetic nanospheres and controllable precession frequency with the sphere diameter 2R, as studied by micromagnetic numerical and analytical calculations. The precession angular frequency for an applied static field HDC is given as ωMV= γeff HDC, where γeff = γ<mΓ> is the effective gyromagnetic ratio in collective vortex dynamics, with the gyromagnetic ratio γ and the average magnetization component <mΓ> of the ground-state vortex in the core direction. Fitting to the micromagnetic simulation data for <mΓ> yields a simple explicit form of <mΓ> = (73.6 ± 3.4)(lex/2R)2.20 ± 0.14, where lex is the exchange length of a given material. This dynamic behavior might serve as a foundation for potential bio-applications of size-specific resonant excitation of magnetic vortex-state nanoparticles, for example, magnetic particle resonance imaging.