Magnetic field SAW sensors based on magnetostrictive-piezoelectric layered structures: FEM modeling and experimental validation

This study describes the numerical implementation of accurate and fully coupled physical models in order to investigate the sensitivity of Surface Acoustic Wave (SAW) devices using the magnetoelastic interaction with an external magnetic field. The model was first validated using experimental data previously published by Kadota et al. obtained with SAW resonators based on quartz substrates and nickel Inter Digital Transducers (IDTs). The model was then used to optimize the geometry of a new magnetostrictive-piezoelectric layered structure (Ni/ZnO/IDT/LiNbO3), regarding its sensitivity to the magnetic field intensity. The optimized structure was designed and fabricated and experimental results show a good correlation with the numerical modeling. Simulations also show that if alumina is used instead of ZnO, the Ni/Al2O3/IDT/LiNbO3 structure exhibits a sensitivity that is 9 times higher than the one based on ZnO.