Formation mechanism of highly [0 0 1]_c textured Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ relaxor ferroelectric ceramics with giant piezoelectricity

We investigated the synthesis mechanism and giant piezoelectricity of highly [0 0 1]_c textured Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PIN-PMN-PT) relaxor based ferroelectric ceramics (texture fraction ~94%) with BaTiO₃ (BT) templates. The onset of texture occurred at ~88% relative density (RD), and rapid increase in texture fraction happened with RD > 94%. A PbO-rich grain boundary liquid of ~6-13 nm thickness, detected at oriented crystalline interfaces, facilitated epitaxial nucleation and subsequent [0 0 1]_PIN-PMN-PT||[0 0 1]_BT growth of textured grains on BT templates. Interfaces between BT templates and PIN-PMN-PT textured grains were found to be coherent and defect-free at the atomic scale, and there was almost no barium diffusion across the interfaces during the texturing process. Nanodomains were clearly visible in the oriented grains. [0 0 1]_c poling ordered the domain structures of textured ceramics and resulted in a more uniform domain size of several hundred nanometers. The textured ternary PIN-PMN-PT ceramics exhibited ~200% improvement in piezoelectric response relative to their random counterparts, as a result of their piezoelectric anisotropy and engineered domain status along with higher mobility of domain walls.