Room-temperature multiferroic Bi4YFeTi3O15 thin films of four-layered perovskite

Polycrystalline Bi4YFeTi3O15 thin films were prepared on (111)Pt/Ti/SiO2/Si through a sol-gel process. X-ray diffraction analysis shows the films have a single-phase four-layered Aurivillius structure with the space group of Fmm2. As expected, the Bi4YFeTi3O15 films exhibit the coexistence of ferroelectric and weak ferromagnetic properties with the remanent polarization (2P(r)) similar to 53.62 mu C/cm(2) and the saturated magnetization (M-s) similar to 0.50 emu/cm(3) at room temperature. More interestingly, both dielectric relaxation behavior and room-temperature magneto-dielectric effect were observed in the Bi4YFeTi3O15 films, probably resulting from the coexistence of Fe2+ and Fe3+. The conduction mechanism of the films from 10 to 300 kV/cm is dominated by Ohmic mechanism, space-charge-limited current (SCLC), and trap filled -limit (TFL) current, respectively. The leakage current density remains lower than 1.03 x 10(-5) A/cm(2) under the poling field below 300 kV/cm at 300 K. (C) 2016 Elsevier B.V. All rights reserved.