Post-deposition control of ferroelastic stripe domains and internal electric field by thermal treatment
The dependence of the formation of ferroelastic stripe domain patterns on the thermal history is investigated by detailed piezoresponse force microscopy and X-ray diffraction experiments after and during annealing of tensile strained tetragonal Pb(Ti,Zr)O-3 epitaxial thin films on DyScO3 substrates. In particular, the ferroelastic pattern is reversibly interchanged between a cross-hatched and a stripe domain pattern if the films are cooled at different rates after annealing above the formation temperature of a-domains. Different types of 180 degrees and non-180 degrees patterns can be created, depending on the thermal treatment. The changes in the 180 degrees domain structure and lattice parameters are attributed to a change of oxygen vacancy concentration, which results in a modification of the internal electric field and unit cell size, causing also a shift of T-C. Thermal treatment is done on rhombohedral La:BiFeO3 thin films as well. It is observed that also in these films, appropriate heat treatment modifies the domain pattern and films with a stripe domain pattern can be created, confirming the general validity of the developed model. (C) 2015 AIP Publishing LLC.