Full text loading...
Lorentz microscopy images of permalloy rings in the circulation state. (a) The Lorentz image of ring array; (b) and (c) are images of two individual rings, with different magnetization circulation helicities revealed by the opposite Lorentz contrast at a given ring boundary. Ring diameters: inner; outer. Thickness: . The images were taken under JEOL 2010 TEM , with the objective lens turned off, and with stray field applied perpendicular to the ring.
Experiment setup and time-domain ferromagnetic resonance curves of Permalloy rings in the circulation state. (a) Schematic drawing of the experimental setup (not to scale). The ring array (not to scale) is placed on top of the coplanar transmission line. The probe beam focuses on the rings through the back side of a transparent substrate patterned with transmission lines. Close to the edge of the transmission lines, only partial rings are exposed to the view of the probe beam. (b) The time-domain FMR curve averaged over an entire ring near the center of the transmission line structure. (c) A time-domain curve corresponding to (b), but locally probed within the ring (as indicated by the inset cartoon). (d) A locally probed response for a ring positioned close to the edge of the transmission line gap (as schematically shown in the inset).
Spectrum amplitudes as a function of the frequency: (a) Fourier transform curve of an entire ring; (b) for focusing part of a ring; and (c) for a ring close to the transmission line. The spectrum amplitude is magnified by a factor of 10 for the frequency between .
Simulation results of time-domain magnetization (a)–(c) and corresponding Fourier transformation (d)–(f) of Permalloy ring in respond to different pulsed field. (a) and (d) Transient field applied perpendicular to the ring; (b) and (e) transient field applied parallel to the ring; (c) and (f) transient field applied with an angle of 10° to the normal direction of the ring. The spectrum amplitude is magnified by a factor of 10 for the frequency from . Insets show the spectrum amplitude map of the ring with dominant spectrum amplitude.
Article metrics loading...