Weak ferromagnetic polar phase in the BiFe1−xTixO3 multiferroics

Neutron powder diffraction and magnetization measurements of selected samples of the BiFe1−xTixO3 series were performed. Ti4+ substitution was shown to induce the appearance of weak ferromagnetism in the initial polar R3c phase stable at x ≤ 0.1. In the concentration range 0 ≤ x ≤ 0.1, room-temperature residual magnetization increases from 0 to 0.25 emu/g (the latter is characteristic of the field-induced weak ferromagnetic state in pure BiFeO3). The calculated ferroelectric polarization decreases from ~70 μC/cm2 (x = 0) to ~60 μC/cm2 (x = 0.1) at room temperature. Magnetic ordering coexists with the large spontaneous polarization in a broad temperature range to make the BiFe1−xTixO3 (x → 0.1) perovskites promising for multiferroic applications.