An improved technique was used to prepare the ceramic samples of Bi_5.75R_0.25Fe_1.4Ni_0.6Ti₃O₁₈ (BRFNT, R = Eu, Sm, Nd, Bi, and La). The five-layer Aurivillius phase of the samples was confirmed by X-ray diffraction (XRD) without detectable impurities. BRFNT samples exhibit the pseudo-tetragonal except the orthorhombic BSmFNT samples. The characteristic plate-like morphology was revealed by field emission transmission electron microscopy (FETEM) images. At ambient temperature, all the samples present both ferroelectric and magnetic properties and BEuFNT shows the best ferroelectric behavior with its remanent polarization as high as 14.9 μC/cm² under 155 kV/cm, which is three times higher than that of Bi₆Fe_1.4Ni_0.6Ti₃O₁₈. Moreover, the remanent magnetization of BEuFNT is increased up to 1.20 emu/g compared to that of Bi₆Fe_1.4Ni_0.6Ti₃O₁₈ which is only 0.53 emu/g. With increasing radius of the introduced A-site ions, the ferroelectric phase transition temperature (T_CE) is decreased while the magnetic phase transition temperature (T_CM) fluctuates. The decrease in both T_CE and T_CM corresponds to the upward shift of the related Raman modes and vice versa, indicating that the T_CE and the T_CM depend not only on the t factor, but also on the strength of the covalent bonds.

改进的技术用于制备 Bi _5.75 R _0.25 Fe _1.4 Ni _0.6 Ti ₃ O ₁₈（BRFNT，R = Eu、Sm、Nd、Bi 和 La）的陶瓷样品。通过 X 射线衍射 (XRD) 确认样品的五层 Aurivilius 相没有可检测的杂质。除了正交 BSmFNT 样品外，BRFNT 样品表现出伪四边形。通过场发射透射电子显微镜 (FETEM) 图像揭示了特征板状形态。在环境温度下，所有样品都表现出铁电和磁性，BEuFNT 显示出最好的铁电行为，其剩余极化高达 14.9 μC/cm ²在 155 kV/cm 以下，是 Bi ₆ Fe _1.4 Ni _0.6 Ti ₃ O _{18 的}三倍。此外，与仅 0.53 emu/g的 Bi ₆ Fe _1.4 Ni _0.6 Ti ₃ O ₁₈相比，BEuFNT 的剩磁增加到 1.20 emu/g。随着引入的 A 位离子半径的增加，铁电相变温度 ( T _CE ) 降低，而磁相变温度 ( T _CM ) 波动。T _CE和T _CM均下降对应于相关拉曼模式的向上移动，反之亦然，表明T _CE和T _CM不仅取决于t因子，还取决于共价键的强度。