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

The current status of studies on the formation of domain structures is revi ewed. Various methods of ferroelectric and magnetic domain formation are di scussed, including putting single crystals to electric, magnetic, optical, and acoustic fields as well as exposing them to a thermal anneal or changin g their chemical composition. It is demonstrated that the realization of in duced domain structures has already led to new frequency multiplication and ultrasound generation methods as well as to those for the parametric trans formation of acoustic and optical beams.