Orientation and stability of domain walls in ferroelectric crystals

An equivalent inclusion method is developed to predict ferroelectric domain structures. It considers energy variation in tetragonal and rhombohedral single crystals when a new domain appears in them. Stable lamellar domain pattern and different domain wall orientations have been identified with energy minimizing. The steady uncharged domain walls and metastable charged domain walls in tetragonal crystals with 900 domain pattern and rhombohedral crystals with 71 degrees and 1090 domain patterns are analyzed respectively, and the results agree well with those observed in experiments. It is also found that the compatibility of transformation strain plays a more important role in domain configurations of tetragonal crystals than polarization compatibility, the action of which is more prominent in rhombohedral ferroelectric crystals, and the incompatibility of piezoelectric strain and the magnitude of applied electric fields are insignificant.