Modeling of High-Sensitivity SAW Magnetic Field Sensors with Au-SiO2 Phononic Crystals

TL;DR

This paper presents a theoretical model for high-sensitivity SAW magnetic sensors using Au-SiO2 phononic crystals, demonstrating significant sensitivity improvements through resonance effects and PnC integration.

Contribution

The study introduces a novel PnC-based design for SAW magnetic sensors that significantly enhances sensitivity compared to previous designs.

Findings

Nearly two orders of magnitude higher sensitivity than similar-sized delay lines.

Eight-fold improvement over previous PnC-based sensor designs.

Resonance effects within PnCs increase SAW-magnetostrictive layer interaction.

Abstract

The development of magnetic field sensors with high sensitivity is crucial for accurate detection of magnetic fields. In this context, we present a theoretical model of a highly sensitive surface acoustic wave (SAW) magnetic field sensor that utilizes phononic crystal (PnC) structures composed of Au pillars embedded within a SiO2 guiding layer. We study rectangular and triangular PnCs and assess their potential for application in thin-film magnetic field sensors. In our design, the PnC is integrated into the SiO2 guiding layer, preserving the continuous magnetostrictive layer and maximizing its interaction with the SAW. The sensor achieves nearly two orders of magnitude higher sensitivity compared to a continuous delay line of similar dimensions and an eight-fold improvement over the previous sensor design with PnCs composed of FeCoSiB pillars. The enhanced sensitivity is attributed to resonance effects within the PnC leading to an increased interaction between the SAW and the continuous FeCoSiB layer covering the PnC. Our results highlight the significant potential of incorporating PnCs into the guiding layer of SAWs for future high performance magnetic field sensors.