Abstract Lead-free Bi4Ti3O12/NiFe2O4 nanocomposite films have been prepared via sol-gel spin-coating route. The successful phase formation of orthorhombic Bi4Ti3O12 and cubic NiFe2O4 has been confirmed using x-ray diffraction without any detectable extra phase. The scanning electron microscopy with EDS measurement reveals homogeneous and dense growth of both phases accompanied by clear interface between the two layers. The loop of magnetization versus magnetic field indicates the ferromagnetic properties at room temperature with saturation magnetization of ~257.48 emu/cm3, coercive field of ~121 Oe and remnant magnetization of ~57.03 emu/cm3. Room-temperature ferroelectric behavior is also obtained along with the good fatigue endurance properties and low leakage current density. The frequency dependence of dielectric constant displays the monotonous decreasing tendency with low dielectric loss. Moreover, evident magnetodielectric behavior is achieved in the nanocomposite films at room temperature. The coexistence of ferromagnetic and ferroelectric behavior including the appearance of magnetodielectric effect proves the room-temperature multiferroic properties in Bi4Ti3O12/NiFe2O4 nanocomposite films, which makes the films meaningful as the lead-free multiferroic systems for device applications at room temperature.

中文翻译：

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无铅Bi4Ti3O12/NiFe2O4纳米复合薄膜的合成及室温多铁性

摘要 采用溶胶-凝胶旋涂法制备了无铅Bi4Ti3O12/NiFe2O4纳米复合薄膜。使用 X 射线衍射证实了正交 Bi4Ti3O12 和立方 NiFe2O4 的成功相形成，没有任何可检测的额外相。具有 EDS 测量的扫描电子显微镜显示两相均匀且致密的生长，伴随着两层之间的清晰界面。磁化强度与磁场的回路表明室温下的铁磁特性，饱和磁化强度为~257.48 emu/cm3，矫顽磁场为~121 Oe，剩余磁化强度为~57.03 emu/cm3。还获得了室温铁电行为以及良好的疲劳耐久性和低漏电流密度。介电常数的频率依赖性表现出单调下降的趋势，介电损耗低。此外，在室温下纳米复合膜中实现了明显的磁介电行为。铁磁和铁电行为的共存，包括磁介电效应的出现，证明了 Bi4Ti3O12/NiFe2O4 纳米复合薄膜的室温多铁性，这使得该薄膜作为室温下器件应用的无铅多铁系统具有重要意义。