The spin dynamics of thin film Permalloy individual rings in the circulating state is studied in the presence of an in-plane bias field and in response to a transient field applied perpendicular to the ring plane. Only one dominant precessional mode is observed in the remanence state, which corresponds to an angularly uniform excitation. In contrast, when an external bias field is applied, multiple precessional modes are observed, with the number of modes increasing as the field increases. The static magnetic field distorts the circular symmetry of the initial magnetization state. As a result, the precessional torque produced by the pulsed field is inhomogeneous, which promotes the excitation of higher order azimuthal modes.
Observation of azimuthal ferromagnetic resonance modes in 1.0 micron diameter Permalloy rings
GIOVANNINI, Loris;MONTONCELLO, Federico;NIZZOLI, Fabrizio;
2006
Abstract
The spin dynamics of thin film Permalloy individual rings in the circulating state is studied in the presence of an in-plane bias field and in response to a transient field applied perpendicular to the ring plane. Only one dominant precessional mode is observed in the remanence state, which corresponds to an angularly uniform excitation. In contrast, when an external bias field is applied, multiple precessional modes are observed, with the number of modes increasing as the field increases. The static magnetic field distorts the circular symmetry of the initial magnetization state. As a result, the precessional torque produced by the pulsed field is inhomogeneous, which promotes the excitation of higher order azimuthal modes.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
