Magnetostructural correlations in BiFeO3-based multiferroics

Inspired by the potential applications of the magnetoelectric effect, interest in multiferroic materials is growing steadily. While BiFeO3 is the most thoroughly studied magnetic ferroelectric compound, the properties of its solid solutions remain a matter of intensive debate. In this paper we show how variation in the chemical composition of Bi1−xAexFe1−xTixO3 (Ae = Ca, Sr, Ba) perovskites affects their crystal structure and magnetic behavior. In particular, our research demonstrates that Ca/Ti and Sr/Ti substitutions suppress the cycloidal antiferromagnetic structure specific to the parent compound, thus stabilizing a weak ferromagnetic ferroelectric state. The Ba/Ti-doped solid solutions retain the magnetic behavior characteristic of the pure BiFeO3. Since the latter observation is directly opposed to the prevailing concept used in describing magnetic phenomena in the Bi1−xBaxFe1−xTixO3 series, the origin of the contradiction between the current and previously reported data is analyzed. Finally, the reasons underlying the difference in the magnetic properties of the Bi1−xAexFe1−xTixO3 compounds are discussed.