We study the structural, ferroelectric, and magnetic properties of the potentially multiferroic Aurivillius phase material ${\mathrm{Bi}}_5{\mathrm{FeTi}}_3{\mathrm{O}}_{15}$ using first-principles electronic structure calculations. Calculations are performed both with PBE and PBEsol exchange correlation functionals. We conclude that PBE systematically overestimates the lattice constants and the magnitude of the ferroelectric distortion, whereas PBEsol leads to good agreement with available experimental data. We then assess a potential site preference by comparing ten different distributions of the ${\mathrm{Fe}}^{3+}\mathrm{cation}$ on the perovskite $B$ sites. We find a slight preference for the “inner” site, consistent with recent experimental observations. We obtain a large value of $\sim 55\mu {\mathrm{C}/\mathrm{cm}}^2$ for the spontaneous electric polarization, which is rather independent of the specific Fe distribution. Finally, we calculate the strength of the magnetic coupling constants and find strong antiferromagnetic coupling between ${\mathrm{Fe}}^{3+}\mathrm{cations}$ in nearest-neighbor positions, whereas the coupling between further neighbors is rather weak. This poses the question whether magnetic long-range order can occur in this system in spite of the low concentration of magnetic ions.

• Received 17 July 2014
• Revised 3 October 2014

DOI:https://doi.org/10.1103/PhysRevB.90.214109