Recent progress on the structural characterizations of domain structures in ferroic and multiferroic perovskite oxides: A review

Multiferroic perovskite oxides have multiple ferroic order parameters simultaneously in the same phase in a certain temperature range, exhibiting an exciting way of coupling between the ferroic order parameters. This provides a possibility for constructing new types of multifunctional devices. Multiferroic domain structures in these materials are considered to be important factors to improve the efficiency and performance of future multiferroic devices. Recent developments in domain characterization techniques, particularly the aberration-corrected transmission electron microscopy (TEM) have enabled one to determine the domain structures at sub-angstrom scale, and the recent development of in-situ TEM techniques allows one to study the dynamic behavior of multiferroic domains under applied fields or stress while the atomic structures are imaged directly. This paper provides a comprehensive review of the recent advances on the structural characterizations of domain structures in ferroic and multiferroic perovskite oxides, which have been achieved by the notable advancement of aberration-corrected TEM.