Domain wall-grain boundary interactions in polycrystalline Pb(Zr0.7Ti0.3)O3 piezoceramics

Abstract

Interactions between grain boundaries and domain walls were extensively studied in ferroelectric films and bicrystals. This knowledge, however, has not been transferred to polycrystalline ceramics, in which the grain size represents a powerful tool to tailor the dielectric and electromechanical response. Here, we relate changes in dielectric and electromechanical properties of a bulk polycrystalline Pb(Zr0.7Ti0.3)O3 to domain wall interactions with grain boundaries. Samples with grain sizes in the range of 3.9-10.4 µm were prepared and their microstructure, crystal structure, and dielectric/electromechanical properties were investigated. A decreasing grain size was accompanied by a reduction in large-signal electromechanical properties and an increase in small-signal dielectric permittivity. High-energy diffraction analysis revealed increasing microstrains upon decreasing the grain size, while piezoresponse force microscopy indicated an increased local coercive voltage near grain boundaries. The changes in properties were thus related to strained material volume close to the grain boundaries exhibiting reduced domain wall dynamics.

Precipitation Hardening in Ferroelectric Ceramics

“…The microstrain can act as a restoring force for switched domains and the high‐domain‐wall‐density regions affected by the microstrain can have higher switching fields, which was evidenced in PZT samples by a previous PFM study. [ 44 ] In contrast to the properties featured in Figure 4d, aging treatment has only little influence on the coercive field, E c , as outlined in Table S1, Supporting Information.…”

“…For the fine domains near the precipitates, a similar phenomenon was observed near the grain boundaries in polycrystalline PZT and was related to increased microstrain. [ 44 ] A decrease in domain size adjacent to Ag intragranular nanoparticles has also been observed in Pb(Zn 1/3 Nb 2/3 ) 0.20 (Zr 0.50 Ti 0.50 ) 0.80 O 3 /6 vol% Ag composites, [ 45 ] while ZrO 2 inclusions have been reported to introduce internal stresses and microcracks in PZT matrix, which inhibited domain wall movement. [ 46 ] Similarly, the regions with fine domains can be attributed to the misfit strain at the precipitate/matrix interface, which arises from the difference in lattice parameters, spontaneous strain, and thermal expansion coefficients of the CT ss and BT ss phases.…”

Defect Engineering in Lead Zirconate Titanate Ferroelectric Ceramic for Enhanced Electromechanical Transducer Efficiency

“…[35a] Recently, Schultheiß et al further investigated the interaction between domain wall and grain boundary in PZT ceramics with different grain sizes (3.9-10 µm). [37] They discovered increased microstrain with decreasing grain size by using high-energy XRD. Meanwhile, by using PFM, they observed a high coercive field in the vicinity of grain boundaries, which might significantly restrict the domain-wall motion.…”

Disentangling Ferroelectric Wall Dynamics and Identification of Pinning Mechanisms via Deep Learning

“…[ 19–21 ] The polar nature of the ferroelectric materials imposes the formation of bound charge at the walls with the discontinuity of polarization, resulting in characteristic instabilities of charged walls [ 22 ] and strong coupling between wall behavior and semiconducting [ 23 ] and electrochemical phenomena at surfaces and interfaces. [ 24,25 ] Notably that while ideal single crystals can form the low energy ground states with a periodic domain wall structure and minimal electrostatic and strain energy, realistic materials evolve complex nonequilibrium domain wall structures [ 26,27 ] due to complex histories, nonlocal effects due to presence of grains and surfaces, [ 28–31 ] and defects and disorder. [ 32–35 ]…”

“…[19][20][21] The polar nature of the ferroelectric materials imposes the formation of bound charge at the walls with the discontinuity of polarization, resulting in characteristic instabilities of charged walls [22] and strong coupling between wall behavior and semiconducting [23] and electrochemical phenomena at surfaces and interfaces. [24,25] Notably that while ideal single crystals can form the low energy ground states with a periodic domain wall structure and minimal electrostatic and strain energy, realistic materials evolve complex nonequilibrium domain wall structures [26,27] due to complex histories, nonlocal effects due to presence of grains and surfaces, [28][29][30][31] and defects and disorder. [32][33][34][35] Over the first half a century of physics of ferroelectrics, exploration of the domain wall dynamics was preponderantly based on theoretical models and macroscopic measurements on samples with multiple domain walls, with the additional insight from relatively low-resolution optical studies using polarized light or chemically etched/decorated samples.…”