The ferroelectric to antiferroelectric transition in multiferroic BiFe$_{1-x}$Cr$_{x}$O$_{3}$ epitaxial films

With the renewed interest in multiferroics, intensive investigations on BiFeO$_{3}$ films have enhanced the understanding of the nature of the ferroelectricity and the weak parasitic ferromagnetism. In contrast, despite having similar structural and chemical properties as BiFeO$_{3}$, little is know about BiCrO$_{3}$, due to the difficulty of synthesizing single-phase material. We have grown high quality BiCrO$_{3}$ epitaxial films by pulsed laser deposition and revealed that they exhibit antiferroelectricity with an electric- field induced ferroelectric phase. This antiferroelectricity is consistent with the picture of the Bi lone pair inducing polarization in bismuth-based perovskites. Furthermore, we have grown BiFe$_{1-x}$Cr$_{x}$O$_{3}$ solid-solution epitaxial films from BiFeO$_{3}$ and BiCrO$_{3}$ targets and observed a ferroelectric to antiferroelectric transition with increasing the Cr content. The interplay between the structural and (anti) ferroelectric properties and the role of the epitaxial strain will be discussed.