Structurally frustrated polar nanoregions in BaTiO_3-based relaxor ferroelectric systems

摘要

This letter presents direct electron diffraction evidence that structurally frustrated one-dimensional polar nanoregions arising from anticorrelated displacements of Ti and nearest neighboring O ions are responsible for the relaxation behavior observed in doped BaTiO_3 relaxor ferroelectrics, rather than chemical short range ordering. The role of the dopant ions is not to directly induce polar nanoregions but rather to set up random local strain fields preventing homogeneous strain distortion, thereby suppressing transverse correlation from one < 001 > chain dipole to the next and hence the development of long range ferroelectric order.