A tunable magneto-acoustic oscillator with low phase noise

TL;DR

This paper presents a tunable magneto-acoustic oscillator with low phase noise, utilizing a YIG/GGG bilayer to achieve frequency tuning from 0.84 GHz to 1 GHz with minimal phase noise.

Contribution

It introduces a novel composite magneto-acoustic oscillator with tunable frequency and low phase noise based on magnetostriction and FMR interaction in a YIG/GGG structure.

Findings

Tunable from 0.84 GHz to 1 GHz with 4.8 MHz steps.

Achieves phase noise of -116 dBc/Hz at 10 kHz offset.

Supports high-quality acoustic modes in YIG/GGG bilayer.

Abstract

A frequency-tunable low phase noise magneto-acoustic resonator is developed on the base of a parallel-plate straight-edge bilayer consisting of a yttrium-iron garnet (YIG) layer grown on a substrate of a gallium-gadolinium garnet(GGG). When a YIG/GGG sample forms an ideal parallel plate, it supports a series of high-quality-factor acoustic modes standing along the plate thickness. Due to the magnetostriction of the YIG layer the ferromagnetic resonance (FMR) mode of the YIG layer can strongly interact with the acoustic thickness modes of the YIG/GGG structure, when the modes' frequencies match. A particular acoustic thickness mode used for the resonance excitations of the hybrid magneto-acoustic oscillations in a YIG/GGG bilayer is chosen by the YIG layer FMR frequency, which can be tuned by the variation of the external bias magnetic field. A composite magneto-acoustic oscillator, which includes an FMR-based resonance pre-selector, is developed to guarantee satisfaction of the Barkhausen criteria for a single-acoustic-mode oscillation regime. The developed low phase noise composite magneto-acoustic oscillator can be tuned from 0.84 GHz to 1 GHz with an increment of about 4.8 MHz (frequency distance between the adjacent acoustic thickness modes in a YIG/GGG parallel plate), and demonstrates the phase noise of -116 dBc/Hz at the offset frequency of 10 kHz.