RÉSUMÉ Ferroelectricity in ABO3 perovskites and related compounds has been a topic of intensive research for more than 60 years. Recently, the coupling of the ferroelectric mode with other structural distortions has attracted an increasing interest since it offers promising and still widely unexplored possibilities to couple ferroelectricity with other functional properties and even to produce unusual phenomena. In this context, the trilinear coupling between ferroelectric and oxygen rotational modes in naturally-occuring and artificial layered perovskites emerged as a practical way to produce unusual dielectric properties or to achieve enhanced magneto-electric coupling. Focusing on titanate and vanadate systems, we will discuss here how even more exciting new phenomena can appear when additional orbital and charge orders enter into play !

for more information : serge.florens@grenoble.cnrs.fr http://lpmmc.grenoble.cnrs.fr/seminaire