A study was made of the effect of normal and shear strains and oxygen vacancies upon the structure of 180° ferroelectric domain walls in PbTiO3. It was known that oxygen vacancies move to the domain walls and pin them. Hence, it was assumed that there was a periodic arrangement of oxygen vacancies on both Pb-centered and Ti-centered domain walls in PbTiO3. A semi-analytical anharmonic lattice statics method was used to obtain the relaxed configurations. using a shell potential. In agreement with recent ab initio calculations, it was observed that a Pb-centered domain wall with oxygen vacancies was not stable even under strain. The semi-analytical calculations for PbTiO3 showed that oxygen vacancies affected the structure of 180° domain walls significantly but did not have a considerable effect on the thickness of domain walls; they broaden the domain walls by about 50%. A study was made of the effect of normal and shear strains on both perfect and defective 180° domain walls. It was observed that normal and shear strains affected the structure but did not change the domain wall thickness.

Effect of Strain and Oxygen Vacancies on the Structure of 180° Ferroelectric Domain Walls in PbTiO3. A.Angoshtari, A.Yavari: Computational Materials Science, 2010, 48[2], 258-66