Tunable mode coupling in nano-contact spin torque oscillators

POSTER

Abstract

Recent experiments on spin-torque oscillators (STOs) have revealed interactions between multiple magnetodynamic modes, including mode coexistence, mode hopping, and temperature-driven crossover between modes. The initial multimode theory indicates that a linear coupling between several dominant modes, arising from the interaction of the subdynamic system with a magnon bath, plays an essential role in the generation of various multimode behaviors. In this work [1], we derive a set of rate equations to describe the dynamics of coupled magnetodynamic modes in a nanocontact STO, and analyze the dependence of the coupled dynamic behaviors of modes on various experimental conditions. For a minimal two-mode system, we further map the energy and phase difference of the two modes onto a 2D phase space and demonstrate in the phase portraits how the manifolds of periodic orbits and fixed points vary with external magnetic field and temperature.
[1] SZ, E. Iacocca, and O. Heinonen, Phys. Rev. Applied 8, 014034 (2017).

*Work by S. Z. and O.H. was supported by the U.S. DOE, Office of Science, BES, Materials Sciences and Engineering Division. Work by S. Z. at the Univ. of Missouri was supported by NSF Grants DMR-1406568. E. I. was supported by the Swedish Research Council, Reg. No. 637-2014-6863.

Presenters

  • Shulei Zhang

    • Materials Science, Argonne National Laboratory
    • Argonne Natl Lab
    • Materials Science Division, Argonne Nat'l Lab; Dept. of Physics and Astronomy, Univ. of Missouri
    • Material Science Division, Argonne Nat'l Lab; Dept. of Physics and Astronomy, Univ. of Missouri

Authors

  • Shulei Zhang

    • Materials Science, Argonne National Laboratory
    • Argonne Natl Lab
    • Materials Science Division, Argonne Nat'l Lab; Dept. of Physics and Astronomy, Univ. of Missouri
    • Material Science Division, Argonne Nat'l Lab; Dept. of Physics and Astronomy, Univ. of Missouri

  • Ezio Iacocca

    • Univ of Colorado - Boulder
    • Dept. of Applied Mathematics, Univ. of Colorado; Dept. of Physics, Division for Theoretical Physics, Chalmers Univ. of Technology

  • Olle Heinonen

    • Argonne National Lab.
    • Materials Science Division, Argonne Nat'l Lab; Northwestern-Argonne Institute of Science and Technology
    • Argonne National Lab
    • Argonne Natl Lab
    • Materials Science Division, argonne national laboratory
    • Materials Science Division, Argonne National Laboratory
    • Argonne National Laboratory