Study on surface and domain structures of PbTiO3 crystals by atomic force microscopy

The surface morphology of flux-grown ${\mathrm{PbTiO}}_3$ crystals is examined by atomic force microscopy (AFM) at room temperature. Surface undulations due to a and c domains are observed on as-grown and heated crystals. The surface bending angle at 90° a-c domain walls is measured to be $\text{(3.58°±0.05°)}$ in good agreement with the theoretical value, 3.6°. Footprints of ancient domains are found to be overlapped by surface undulations of the actual domain after polishing and heating process. Reciprocal 180° domains embedded in a and c domains are observed by both AFM and by polarizing optical microscopy on etched crystals. Details of the etched pattern are explored. Contrary to abrupt changes of height at 180° walls in c domains, only very small grooves are detected at 180° walls in a domains.