Induced domains and periodic domain structures in electrically and magnetically ordered materials

The state of the art of studies of the formation of domain structures is reviewed. Various methods of ferroelectric and magnetic domain formation are discussed, including putting single crystals into electric, magnetic, optical, and acoustic fields as well as exposing them to thermal annealing or changing their chemical composition. It is demonstrated that the realization of induced domain structures has already led to new frequency multiplication and ultrasound generation methods as well as to those for the parametric conversion of acoustic and optical beams. (reviews of topical problems)