Ferroelectric distortions in doped ferroelectrics: BaTiO3:M (M = V-Fe)

A major challenge in the search for multiferroic materials among transition metal compounds has been that ferroelectricity is primarily found in d(0) materials while magnetism is found in d(n) systems. Considering a well-known ferroelectric oxide, namely BaTiO3, the question we asked within a theoretical study was whether ferroelectric distortions disappeared for the slightest amount of doping. Surprisingly, in the case of V-doped BaTiO3, ferroelectricity was found to be stronger than in the undoped limit. Another surprise was that the presence of charged impurities rather than free carriers was found to be most detrimental to the presence of ferroelectric distortions. These ideas of the low doping limit were used to design alternative multiferroics.