Magnonic spontaneous oscillation induced by parametric pumping

TL;DR

This paper introduces a novel mechanism for generating magnetic spontaneous oscillations through parametric pumping, enabling tunable spin wave dynamics and high-gain magnonic amplification, advancing nonlinear magnonics and synchronization research.

Contribution

It demonstrates a new parametric pumping method to induce spontaneous magnon oscillations and develop high-gain magnonic amplifiers, expanding the capabilities of nonlinear magnonic devices.

Findings

Generated ultrasharp spin wave dynamics with broad frequency tunability.

Achieved phase-locking of spontaneous modes to a probe tone.

Realized a magnonic parametric amplifier with up to 40 dB gain.

Abstract

Spontaneous dynamic systems have attracted significant attention for their rich underlying physics such as phase-locking and synchronization. In this work, we report a new mechanism of generating magnetic spontaneous oscillation via parametric pumping. By applying a pump tone to excite propagating spin waves in a yttrium iron garnet delay line, four-wave mixing converts the pump mode into two phase-autonomous propagating magnon modes, i.e. a spontaneous mode with nearly twice the wavenumber of the pump mode and an idler mode with nearly zero wavenumber. This allows us to reliably generate ultrasharp spin wave dynamics with broad frequency tunability from the pump and magnetic field. We show that the spontaneous mode can be phase-locked to a probe tone, similar to an auto-oscillator. Furthermore, the spontaneous dynamics can be used to implement a high-gain magnonic parametric amplifier with a gain up to 40 dB. Our results open a new avenue for studying nonlinear magnonics and synchronization physics in propagating magnon geometry and for developing new magnonic devices.