A skyrmion-based spin-torque nano-oscillator

• Published in: New journal of physics Vol. 18; no. 7; pp. 75011 - 75020
• Main Authors: Garcia-Sanchez, F, Sampaio, J, Reyren, N, Cros, V, Kim, J-V
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 14.07.2016; Institute of Physics: Open Access Journals
• Subjects: Anisotropy; Computational fluid dynamics; Computer simulation; Condensed Matter; Dzyaloshinskii-Moriya interaction; Gyration; Hypothetical particles; magnetisation dynamics; Particle theory; Phenomenology; Physics; Polarization (spin alignment); skyrmions; spin-torque nano-oscillators; spin-transfer torques; Thin films; Torque; skyrmions; spin-torque nano-oscillators; magnetisation dynamics; Dzyaloshinskii-Moriya interaction; spin-transfer torques
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/18/7/075011

A model for a spin-torque nano-oscillator based on the self-sustained oscillation of a magnetic skyrmion is presented. The system involves a circular nanopillar geometry comprising an ultrathin film free magnetic layer with a strong Dzyaloshinkii-Moriya interaction and a polariser layer with a vortex-like spin configuration. It is shown that spin-transfer torques due to current flow perpendicular to the film plane leads to skyrmion gyration that arises from a competition between geometric confinement due to boundary edges and the vortex-like polarisation of the spin torques. A phenomenology for such oscillations is developed and quantitative analysis using micromagnetics simulations is presented. It is also shown that weak disorder due to random anisotropy variations does not influence the main characteristics of the steady-state gyration.