Spin-torque-induced dynamics at fine-split frequencies in nano-oscillators with two stacked vortices

• DOI: 10.1038/ncomms7409
• Publication Date: 2015-03-03T10:54:44Z
• Authors: V. Sluka; A. Kákay; A. M. Deac; D. E. Bürgler; C. M. Schneider; R. Hertel
• Keywords: Oscillation (cell signaling); Gyration

The gyrotropic rotation around the equilibrium position constitutes fundamental excitation of magnetic vortices in nanostructures. frequency this mode varies with material and sample geometry, but is independent vortex handedness its core direction. Here, we demonstrate that degeneracy lifted a spin-torque oscillator containing two stacked on top each other. When driven by spin-polarized currents, such devices exhibit set dynamic modes discretely split frequencies, corresponding to specific combination vorticities relative polarities. fine splitting occurs even absence external fields, demonstrating can function as zero-field, multi-channel, nano-oscillators for communication technologies. It also facilitates detection polarization allows eight non-degenerate configurations be distinguished electrically, which may enable design multi-state memory based double-vortex nanopillars. Magnetic nanodiscs possess potential applications their configuration spin-torque-driven oscillation. Sluka et al. show how coupled gyration into discretized frequencies defined chirality polarity.