Abstract
Magnetoelectric cantilevers consisting of strain-coupled magnetostrictive and piezoelectric (PE) layers are applicable to magnetic-field sensing. For the first bending mode, the magnetic field-induced stress distribution is of equal sign along the cantilever length. Thus, a plate-capacitor electrode configuration encompassing the complete PE layer may be used for collecting the strain-induced charge. For higher order modes, stress regions of the opposite sign occur in the cantilever length direction. To prevent charge cancellation and to harvest the piezoelectric induced charge efficiently, segmented electrodes are employed. This study investigates the effect of the electrode configuration on the signal-to-noise ratio (SNR) for higher order bending modes. The charges collected by the electrodes are calculated using a finite element method simulation considering the mechanical, electrical, and magnetic properties of the cantilever. By combination with an analytic noise model, taking into account the sensor and amplifier noise sources, the SNR is obtained. We analyze a 3 mm long, 1 mm wide, and 50 μm thick silicon cantilever with layers of 2 μm magnetostrictive soft amorphous metal (FeCoSiB) and 2 μm piezoelectric aluminum nitride. We demonstrate that an SNR-optimized electrode design yields an SNR improvement by 2.3 dB and 2.4 dB for the second and third bending modes compared to a signal optimized design.
Highlights
Magnetoelectric (ME) cantilevers are employed for energy harvesting,1,2 as well as for measuring magnetic fields at roomtemperature.3–5 In both cases, a magnetostrictive (MS) layer and a piezoelectric (PE) layer are used for the conversion of a magnetic field to an induced electric charge by strain coupling of the two layers—with or without an additional substrate
This study investigates the effect of the electrode configuration on the signal-to-noise ratio (SNR) for higher order bending modes
Our finite-element method (FEM) study shows that the SNR-based design of the electrodes for the analyzed sensor setup improves the higher-mode sensor performance by up to 2.4 dB
Summary
Magnetoelectric (ME) cantilevers are employed for energy harvesting, as well as for measuring magnetic fields at roomtemperature. In both cases, a magnetostrictive (MS) layer and a piezoelectric (PE) layer are used for the conversion of a magnetic field to an induced electric charge by strain coupling of the two layers—with or without an additional substrate. In contrast to previous studies on electrode designs for higher order modes, we design the electrode configuration for maximum SNR instead of sensitivity. In the first part of this study, a FEM model was implemented for the calculation of the signal strength for higher order bending modes. This model, considering the mechanical, electrical, and magnetic properties of the composite cantilever, was verified by experimental results obtained with 45 mm long and 5 mm wide silicon cantilevers with poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF–TrFE)] as a piezoelectric and Metglas as a magnetostrictive layer [Figs. 3 mm long and 1 mm wide silicon cantilevers with active layers of aluminum nitride (AlN) and Metglas were investigated, as these cantilevers were shown to exhibit a low limit of detection for magnetic-field sensing compared to the one chosen for model verification
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
