Room-temperature multiferroic properties of sol-gel derived 0.5LaFeO3-Bi4Ti3O12 thin films with layered perovskite

Random-oriented 0.5LaFeO3-Bi4Ti3O12 thin films were prepared via a sol-gel method on (111)Pt/Ti/SiO2/Si(100) substrates. According to X-ray diffraction analysis, the films have a single-phase Aurivillius perovskite structure with a space group Fmm2. As expected, the coexistence of ferroelectric and ferromagnetic properties was detected at room temperature. The remanent polarization (2Pr) and the saturated magnetization (Ms) are 61.94 μC/cm2 and ∼0.90 emu/cm3, respectively. Furthermore, a magneto-dielectric effect was demonstrated at room temperature with a magneto-dielectric coefficient of 0.67% under a low magnetic field of 0.25 T, probably resulting from the charge ordering of Fe2+ and Fe3+. Finally, a dielectric relaxation behavior was observed around 130 K, which is also related to the coexistence of Fe2+ and Fe3+.