Report on the piezoelectric frequency effect in quartz and its possibility in other piezoelectric materials

TL;DR

This study demonstrates a voltage-induced eigen-frequency shift in quartz tuning forks due to internal stress, suggesting the piezoelectric frequency effect could be utilized in high-precision, fast-response voltage-controlled oscillators across all piezoelectric materials.

Contribution

It reveals the piezoelectric frequency effect in quartz and proposes its potential application in developing ultra-precise, rapid-response voltage-controlled oscillators.

Findings

Eigen-frequency shifts depend parabolically on applied voltage.

The effect is due to voltage-induced internal stress.

Coefficient of frequency shift is in the nano-Hz per millivolt range.

Abstract

We report the eigen-frequency shift induced by an applied voltage on quartz material. The samples are in the form of commercial 32 KHz quartz tuning forks used in watches. Three vibration modes are studied: one prong oscillates, two prongs oscillate in the same and opposite directions. They all show a parabolic dependence of the eigen-frequency shift on the bias voltage applied across the fork, which is explained owing to the voltage-induced internal stress that varies as the fork oscillates. Thus, this piezoelectric frequency effect is possible to exist in all piezoelectric materials. The average coefficient of the piezoelectric frequency effect is as low as several hundred nano-Hz per millivolt, implying that the most precise (nano-Hz) yet fast-response voltage-controlled oscillators and phase-locked loops can be built.