ABSTRACT
High-power piezoelectric material’s development, based on the loss mechanisms, are introduced in this chapter “Loss Mechanisms in Piezoelectrics”. Practical high-power “hard” Pb(Zr, Ti)O3 (PZT)-based materials are initially described, which exhibit vibration velocities close to 1 m/s (rms), leading to the power density capability ten times that of the commercially available “hard” PZTs. Based on the macroscopic phenomenological study results, we consider microscopic crystallographic and semi-microscopic domain wall dynamics models to understand the experimental results. Impurity dipole alignment categories include: (1) random alignment – higher coercive field – “domain wall pinning” model, (2) unidirectionally fixed alignment – internal bias field, and (3) unidirectionally reversible alignment – pinched/double hysteresis. We detail an internal bias field model to explain the low-loss and high-power origin of these materials. The discussion is expanded to Pb-free piezoelectrics, which have been developed recently. The latter part of this chapter is devoted to the phenomenological handling of the domain wall dynamics, based on Ginzburg–Landau functional.
