Discontinuous switching in antiferroelectric ceramics monitored by acoustic emissions

Acoustic emission patterns were monitored during electric-field-induced antiferroelectric to ferroelectric phase transitions for fine- and coarse-grained antiferroelectric lead lanthanum zirconate stannate titanate ceramics $[Pb0.97La0.02(Zr0.77Sn0.14Ti0.09)O3]$⁠. For the initial phase-transition cycle, acoustic emissions were detected just before and right after the major strain changes. During subsequent cycles, the strain response becomes jumplike and associated with additional acoustic emissions. Acoustic emissions before strain changes are assigned to domain nucleation and those at high fields to domain jumps, nucleation-annihilation processes, or microcracking. The intermediate ones are associated with defect charge rearrangement within the material. Backswitching generates acoustic emissions in the fine-grained material but only for certain drive conditions in the coarse-grained ceramic. Implications for domain nucleation processes, strain, and the role of defects in antiferroelectrics are discussed.