Nonlinear spin-wave excitations at low magnetic bias fields

Bauer, Hans G. and Majchrak, Peter and Kachel, Torsten and Back, Christian H. and Woltersdorf, Georg (2015) Nonlinear spin-wave excitations at low magnetic bias fields. NATURE COMMUNICATIONS, 6: 8274. ISSN 2041-1723,

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Abstract

Nonlinear magnetization dynamics is essential for the operation of numerous spintronic devices ranging from magnetic memory to spin torque microwave generators. Examples are microwave-assisted switching of magnetic structures and the generation of spin currents at low bias fields by high-amplitude ferromagnetic resonance. Here we use X-ray magnetic circular dichroism to determine the number density of excited magnons in magnetically soft Ni80Fe20 thin films. Our data show that the common model of nonlinear ferromagnetic resonance is not adequate for the description of the nonlinear behaviour in the low magnetic field limit. Here we derive a model of parametric spin-wave excitation, which correctly predicts nonlinear threshold amplitudes and decay rates at high and at low magnetic bias fields. In fact, a series of critical spin-wave modes with fast oscillations of the amplitude and phase is found, generalizing the theory of parametric spin-wave excitation to large modulation amplitudes.

Item Type: Article
Uncontrolled Keywords: FERROMAGNETIC-RESONANCE; THIN-FILMS; INSTABILITY; PERMALLOY; DRIVEN; REGIME;
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors
Depositing User: Dr. Gernot Deinzer
Date Deposited: 11 Jun 2019 12:48
Last Modified: 11 Jun 2019 12:48
URI: https://pred.uni-regensburg.de/id/eprint/4876

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