Ferroelectric and ferromagnetic properties of Bi7−xLaxFe1.5Co1.5Ti3O21 ceramics prepared by the hot-press method

Six-layered Aurivillius Bi7−xLaxFe1.5Co1.5Ti3O21 (BLFCT) powders and ceramics were prepared by citrate combustion and hot-press methods. X-ray diffraction indicates a successful synthesis of BLFCT ceramics. At room temperature, the largest remnant polarization (2Pr ∼4.02 μC/cm2) and remnant magnetization (2Mr ∼2.58 emu/g) were observed at a La concentration of x = 0.75. Dielectric and zero-field cooling-field cooling (ZFC-FC) magnetization measurements confirm its ferroelectric and magnetic transitions occurring at ∼1009 K and ∼505 K, respectively. Positive-up-negative-down (PUND) measurement indicates an intrinsic ferroelectricity, and the leakage current does not play a big role in the BLFCT ceramics. Besides, the effect of La substitution on 2Pr and 2Mr was also discussed.