Micromagnetic Modeling of Nanocontact Spin-Torque Oscillators With Perpendicular Anisotropy at Zero Bias Field

• Published in: IEEE transactions on magnetics Vol. 44; no. 11; pp. 2512 - 2515
• Main Authors: Puliafito, V., Azzerboni, B., Consolo, G., Finocchio, G., Torres, L., Diaz, L.L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.11.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Anisotropy; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Excitation; Frequency; Hysteresis; Magnetic devices; Magnetic hysteresis; Magnetism; Magnetization; Magnetoelectronics; Materials science; Micromagnetics; Nanocomposites; Nanomaterials; Nanoscale devices; Nanostructure; Nonlinear oscillators; Numerical analysis; Oscillators; Other topics in materials science; perpendicular magnetic anisotropy; Physics; spin-waves; Sustaining; vortex dynamics; spin-waves; perpendicular magnetic anisotropy; Magnetic anisotropy; vortex dynamics; Nonlinear oscillators; Modelling; Oscillators; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2008.2002596

In this paper, we present a numerical study to determine the feasibility of exciting and sustaining stable magnetization oscillations in magnetic nanocontact devices subjected to the combined action of a spin-polarized current and a perpendicular anisotropy field when no external field is applied. A systematic numerical analysis of the properties exhibited by such spintronic oscillators is carried out by means of a micromagnetic framework. The study reveals a nonlinear behavior of the excited frequency as the anisotropy field strength is varied. More noteworthy, full-scale investigations result in a hysteretic dependence of the excited frequency on the applied current together with the existence of two kinds of precessional spin-wave modes: an anisotropic radially propagating mode and a gyrotropic motion of a magnetic vortex-core.