We present a method to calculate the magnetic normal modes of a ferromagnetic nano-particle. The method is a hybrid of micromagnetic simulations and a dynamical matrix approach. We use the method to calculate the normal modes of a 116x60x20 nm Fe parallelepiped, in external field applied in the direction of the long axis. We find two families of spin modes which exhibit, at least to first approximation, standing-wave character with wavevector parallel and perpendicular to the applied field, respectively. With reference to film excitations, the former are assigned as backward-like, the latter as Damon-Eshbach-like modes. In addition, spin excitations localized at the particle ends, in the direction of the applied field, are found. We also observe hybridization effects, which limit the validity of the over-simplified standing-wave picture.
Magnetic normal modes in nanoparticles
GIOVANNINI, Loris;MONTONCELLO, Federico;NIZZOLI, Fabrizio;
2004
Abstract
We present a method to calculate the magnetic normal modes of a ferromagnetic nano-particle. The method is a hybrid of micromagnetic simulations and a dynamical matrix approach. We use the method to calculate the normal modes of a 116x60x20 nm Fe parallelepiped, in external field applied in the direction of the long axis. We find two families of spin modes which exhibit, at least to first approximation, standing-wave character with wavevector parallel and perpendicular to the applied field, respectively. With reference to film excitations, the former are assigned as backward-like, the latter as Damon-Eshbach-like modes. In addition, spin excitations localized at the particle ends, in the direction of the applied field, are found. We also observe hybridization effects, which limit the validity of the over-simplified standing-wave picture.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
