Flexoelectric barium strontium titanate (BST) hydrophones
- 11 February 2021
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 129 (6), 064504
- https://doi.org/10.1063/5.0038756
Abstract
Flexoelectric hydrophones offer the possibility of reasonable sensitivity in lead-free systems. In this work, a dense barium strontium titanate ceramic with a Ba:Sr ratio of 70:30 and an effective flexoelectric coefficient, 12, of 105.6 ± 0.6 μC/m at room temperature was utilized in a prototype three-point bending hydrophone with dimensions of 77 × 10 × 0.67 mm3. Tap testing of this hydrophone with a calibrated acoustic hammer showed a resonant frequency of 250 Hz and a maximum sensitivity of 80 pC/N. Finite element analysis (FEA) was employed to verify the experimental results and to refine the predictive modeling capability. FEA was used to predict the resonant frequency of devices based on geometry, boundary conditions, and material properties. The error in resonant frequency between the FEA model and the experiment was 7.6%. FEA also enables calculations of the strain gradient produced in a material, allowing the numerical analysis of the element's expected flexoelectric output. Using this technique, single and three bending point hydrophone designs were compared. The results showed a 43% increase in charge output in the three bending point design vs the single bending point design despite an average strain decrease of 48% in each electrode pair. This design would lower the voltage output by 48% in a voltage-based design unless the voltages could be added in series. FEA studies also found the greatest flexoelectric output at low frequencies with improved high frequency output using larger electrode areas.
Keywords
Funding Information
- Office of Naval Research (N000141812471)
This publication has 7 references indexed in Scilit:
- Flexoelectricity in solids: Progress, challenges, and perspectivesProgress in Materials Science, 2019
- A flexoelectric microelectromechanical system on siliconNature Nanotechnology, 2015
- Residual ferroelectricity in barium strontium titanate thin film tunable dielectricsJournal of Applied Physics, 2014
- Fundamentals of flexoelectricity in solidsNanotechnology, 2013
- Flexoelectric Effect in SolidsAnnual Review of Materials Research, 2013
- Flexure mode flexoelectric piezoelectric compositesJournal of Applied Physics, 2009
- Flexoelectric polarization of barium strontium titanate in the paraelectric stateApplied Physics Letters, 2002