Compressive stress effect on the loss mechanism in a soft piezoelectric Pb(Zr,Ti)O₃

High power piezoelectric devices are often subjected to external mechanical biases, in applications such as underwater transducers. While the performance of these devices under external pressure has been rather extensively studied, there is a lack of study on the loss mechanism in terms of three dielectric, elastic, and piezoelectric losses. Thus, in this paper, we study the mechanical bias stress dependence of the loss mechanism in a soft piezoelectric Pb(Zr,Ti)O₃ (PZT) from a scientific viewpoint, using an equivalent circuit methodology based on the fundamental longitudinal mode. In order to measure the loss behavior, a modified bolt-clamped Langevin transducer was designed and optimized using finite element analysis in order to facilitate the analysis easier. We present the preliminary experimental part of our project on the design of the proposed structure/methodology, material creep behavior, stress relaxation, and uniform stress distribution, in order to minimize the experimental errors. We also introduce a six terminal equivalent circuit analysis in order to determine three losses in the PZT specimen. The resonance/antiresonance frequencies and quality factors showed monotonous increase under compressive stress. Loss factors for one PZT composition are reported in this paper to show the feasibility of our methodology for measuring the uniaxial compressive stress dependence.