title: Resonant vortex-core reversal in magnetic nano-spheres as robust mechanism of efficient energy absorption and emission.
abstract: We report on novel vortex-core reversal dynamics in nano-spheres of single-vortex spin configuration as revealed by micromagnetic simulations combined with analytical derivations. When the frequency of an AC magnetic field is tuned to the frequency of the vortex-core precession around the direction of a given static field, oscillatory vortex-core reversals occur, and additionally, the frequency is found to change with both the strength of the applied AC field and the particle size. Such resonant vortex-core reversals in nano-spheres may provide a new and efficient means of energy absorption by, and emission from, magnetic nanoparticles, which system can be effectively implemented in bio-applications such as magnetic hyperthermia.
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: Jae-Hyeok
authors.initials: JH
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: Min-Kwan
authors.initials: MK
authors.lastname: Kim