Multiferroic and dielectric properties of Bi4LaTi3FeO15 ceramics

Single phase Bi4LaTi3FeO15 ceramics with a four-layered Aurivillius structure were synthesized by successfully inserting LaFeO3 into Bi4Ti3O12 matrix, and their structural, multiferroic and dielectric properties were investigated. Typical ferroelectric behavior with remnant polarization (2Pr) of about 12 μC/cm2, large dielectric constant, small dielectric loss and a weak ferromagnetic behavior are obtained simultaneously at room temperature. As a result, possible magnetoelectric coupling effect is obtained near the ferromagnetic Curie temperature. Meanwhile, the weak ferromagnetism can be enhanced at lower temperature, and thus a larger saturation magnetization of about 1.2 emu/g is obtained at 5 K. In addition, two sets of dielectric relaxation are observed and discussed based on defect relaxation theory.