Spin-wave dynamics in a ferrimagnetic sphere

Paul H. Bryant, Carson D. Jeffries, and Katsuhiro Nakamura
Phys. Rev. A 38, 4223 – Published 1 October 1988
PDFExport Citation

Abstract

An experimental study is made of the interactions between spin-wave modes excited in a sphere of yttrium iron garnet by pumping the Suhl subsidiary absorption at 9.2 GHz with the dc field parallel to [111]. The dynamical behavior of the magnetization is observed under high resolution by varying two control parameters, dc field (580 Oe<H<2100 Oe) and microwave pump power (1 mW<P<200 mW). Within this parameter space quite varied behavior is found: (i) onset of the Suhl instability by excitation of a single spin-wave mode with very narrow linewidth (<0.5 G); (ii) when two or more modes are excited, interactions lead to auto-oscillations with a systematic dependence of frequency (104106 Hz) on pump power these oscillations displaying period doubling to chaos; (iii) quasiperiodicity, locking, and chaos occur when three or more modes are excited; (iv) abrupt transition to wide-band power spectra (i.e., turbulence), with hysteresis; (v) irregular relaxation oscillations and aperiodic spiking behavior. A theoretical model is developed from first principles, using the plane-wave approximation and including anisotropy effects, obtaining the lowest-order nonlinear interaction terms between the excited modes. Bifurcation behavior is examined, and dynamical behavior is numerically computed and compared to the experimental data, explaining a number of features. A theory is developed regarding the nature of the experimentally observed relaxation oscillations and spiking behavior based on the interaction of ‘‘weak’’ and ‘‘strong’’ modes, and this is demonstrated in the numerical simulations.

  • Received 7 April 1988

DOI:https://doi.org/10.1103/PhysRevA.38.4223

©1988 American Physical Society

Authors & Affiliations

Paul H. Bryant and Carson D. Jeffries

  • Department of Physics, University of California, Berkeley, California 94720
  • Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720

Katsuhiro Nakamura

  • Fukuoka Institute of Technology, Higashi-ku, Fukuoka 811-02, Japan

References (Subscription Required)

Click to Expand
Issue

Vol. 38, Iss. 8 — October 1988

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review A

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×