Fig. 1. Schematic domain configurations in SBT^[10]: (a) Original; (b) the translational domain pair; (c) the 180° (rotational) domain pair; (d) the 90° domain pair; (e) the translational –180° domain pair; (f) the translational –90° domain pair.

Fig. 2. TEM observation of the domain structure in SBT^[4,11]: (a), (b) TEM dark field images at different time; (c) and (d) the depicted domain patterns of panels (a) and (b) respectively, with arrows showing the polarization directions. The red, blue and black lines are the antiphase boundary, 180^o domain wall and 90° domain wall in SBT, respectively.

Fig. 3. Internal friction related with oxygen vacancies in ferroelectric ceramics^[17]: (a) Internal friction of BiT and BNT ceramics with temperature; (b) internal friction of BNT ceramics before and after poling.

Fig. 4. Stress effect in BLT films^[28,31,32]: (a) Normalized remnant polarization with stress for films with different grain sizes; (b) fatigue properties under stress; (c) schematic diagram of stress-induced-polarization-reorientation; (d) in-situ PFM observation of stress-induced-polarization-reorientation.

Fig. 5. Polarization switching in polycrystalline BFO films^[37]: (a) Displacement along z direction; (b) examples for 71°, 109° and 180° domain switching.

Fig. 6. Domain growth in LN crystals^[39,42]: (a) Decay process of domains with various initial radii; (b) critical initial domain radius as a function of sample thickness; (c) PFM phase images of linear domains along different directions; (d) poling voltage dependence of domain width and irregularity of linear domains.

Fig. 7. Polarization relaxation in LN single crystals^[52]: PFM phase images in (a) 17 min and (b) 68 min after poling with 80 V; (c) final fraction of switched domains with poling voltage; (d) nucleation time and dimension of domain growth with voltage.

Fig. 8. Abnormally switched domains in LN crystals^[57]: (a) Piezoresponse phase images after poling with various pulse voltages; (b) internal radius as a function of pulse magnitude; (c) decay process after poling; (d) lifetime of internal domains with poling conditions.

Fig. 9. Ferroelectric topological domains^[68]: (a) Schematic of vortex and antivortex structures; (b) three pairs of vortex-antivortex formed near the BFO 71° domain wall.

Fig. 10. Conductive domain walls in BFO films^[85]: (a) c-AFM image and domain pattern; (b) schematic of domain configuration in the dipole-tunneling model and effect of tip-surface barrier on the simulated current; (c) simulated potential and current images.

Fig. 11. Conductive domain walls in LN crystals^[86]: (a) Cross section obtained by 3D Cherenkov second-harmonic-generation microscopy, c-AFM image, and cross section of the c-AFM image; (b) sketches for domain walls with different roughness, simulated current distribution for the rough domain walls, and cross section of the simulated current.

Fig. 12. LSMO/BFO heterostructure^[89]: Anisotropic (a) transport and (b) magnetoresistance of LSMO/BFO heterostructure with 71° domain structure; (c) Schematics and (d) anisotropic transport of LSMO (30 nm)/BFO (30 nm) heterostructure with 109° domain pattern.