Fingerprints of relaxor ferroelectrics: Characteristic hierarchical domain configurations and quantitative performances

Ferroelectrics’ structure-property relationships are of guiding significance in high-performance material designing and usually clarified from the aspect of symmetries, which is arduous and costly. On the principle of convenience, here, the concept that domains can provide a brandnew nondestructive and fast way for this relationship clarification is demonstrated. Utilizing scanning probe microscopy, quantitative original local elastic/piezoelectric/ferroelectric performances of various characteristic domain configurations are directly investigated in relaxor ferroelectric Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ single crystals. Among them, the polygonal lamellar domains with coexistence of straight c, a and c/a walls in the at-morphotropic phase boundary composition, own high surface effective Young's modulus (average values close to 160 GPa), strong original average local piezoresponse (8.5 pm) and effective longitudinal piezoelectric response (d₃₃, 14 pm V⁻¹), together with ease of electrical switching. Low free energy barrier and strong piezoelectric anisotropy contribute intrinsically to these better functionalities. Higher and easier domain wall motion, larger ratio of c⁺/c⁻ domains, and larger depolarization and elastic energies stemmed from larger domain width/size act as extrinsic factors. These results help to understand relaxor ferroelectrics comprehensively and provide a reference of domain-based structure selection for better material design.