Electron Transfer Between Ionized Vacancies in Lead Zirconate Titanate and its Effects on Piezoelectric Properties and Squeeze Behavior

Intrinsic double ionized lead vacancies and oxygen vacancies simultaneously exist within PZT compositions and create a defect dipole. Acceptor dopants with a valence of +3 induce extrinsic single ionized oxygen vacancies whereas donor dopants with a valence of +5 induce extrinsic single ionized lead vacancies. An electron exchange can exist between single and double ionized vacancies that it was facilitated in the case of single ionized lead vacancies. As a consequence, such a transfer occurred mainly for soft PZT and almost never for hard PZT. Based on this transfer, this paper explains the softening effect and the squeeze ignition mechanism.