| Bistability of vortex core dynamics in a single perpendicularly magnetized nano-disk (2008) | |||||||||||||||
Abstract | |||||||||||||||
| Microwave spectroscopy of individual vortex-state magnetic nano-disks in a perpendicular bias magnetic field, $H$, is performed using a magnetic resonance force microscope (MRFM). It reveals the splitting induced by $H$ on the gyrotropic frequency of the vortex related to the existence of the two stable polarities of the core. This bistability extends up to a large negative (antiparallel to the core) value of the bias magnetic field $H_r$, at which the core polarity is reversed. The difference between the frequencies of the two stable rotational modes of each polarity is proportional to $H$ and to the ratio of the disk thickness to its radius. Simple analytic theory in combination with micromagnetic simulations give quantitative description of the observed bistable dynamics. | |||||||||||||||
Details der Publikation | |||||||||||||||
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