title: Resonantly excited precession motion of three-dimensional vortex core in magnetic nanospheres [corrected].
abstract: 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 = γeffHDC, 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.
authors.affiliation: National Creative Research Initiative Center for Spin Dynamics and Spin-Wave Devices, Nanospinics Laboratory, Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: Sang-Koog
authors.initials: SK
authors.lastname: Kim
authors.affiliation: National Creative Research Initiative Center for Spin Dynamics and Spin-Wave Devices, Nanospinics Laboratory, Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: Myoung-Woo
authors.initials: MW
authors.lastname: Yoo
authors.affiliation: National Creative Research Initiative Center for Spin Dynamics and Spin-Wave Devices, Nanospinics Laboratory, Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: Jehyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: National Creative Research Initiative Center for Spin Dynamics and Spin-Wave Devices, Nanospinics Laboratory, Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: Ha-Youn
authors.initials: HY
authors.lastname: Lee
authors.affiliation: National Creative Research Initiative Center for Spin Dynamics and Spin-Wave Devices, Nanospinics Laboratory, Research Institute of Advanced Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, South Korea.
authors.forename: Jae-Hyeok
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Bogolyubov Institute for Theoretical Physics, 03680 Kiev, Ukraine.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Gaididei
authors.affiliation: Bogolyubov Institute for Theoretical Physics, 03680 Kiev, Ukraine.
authors.forename: Volodymyr P
authors.initials: VP
authors.lastname: Kravchuk
authors.affiliation: Taras Shevchenko National University of Kiev, 01601 Kiev, Ukraine.
authors.forename: Denis D
authors.initials: DD
authors.lastname: Sheka