Advanced synthesis techniques and routes to new single-phase multiferroics

► Multiferroic materials which possess two or more ferroic order parameters are reviewed. ► Multiferroics are rare and modern thin-film growth techniques provide high-quality samples. ► Epitaxial thin-film strain is a key parameter in the growth, design, and control of multiferroics. ► Recent advances in strain-engineering of multiferroics such as EuTiO3 and BiFeO3 are reviewed.