Bi0.975La0.025Fe0.975Ni0.0255O3 (BLFNO) ferroelectric film was fabricated on Pt/Ti/SiO2/Si (111) substrate by a solgel process.X-ray diffraction system (XRD),atomic force microscope (AFM),piezoresponse force microscopy (PFM) were used to characterize the crystal structure,morphology,and ferroelectric domain information.It was found that the well-crystallized perovskite BLFNO film is polyerystalline with grains almost uniformly distributed.Very obvious domain structures could be observed from the PFM image,indicating different orientaions of the grains related to ferroelectric domains.Moreover,it was found that Pt/BLF-NO/Pt ferroelectric capacitor possesses very good ferroelectric properties,as the remnant polariztion is 74.3 μC/cm2 under 828 kV/cm electric field,which demonstrated that the La and Ni co-doping does not obviously decrease the remnant polarization of the capacitor.Compared to the pure BFO film,La and Ni co-doping can lower the leakage current density of Pt/BLFNO/Pt capacitor to the magnitude of 10-4 A/cm2 under 277.8 kV/cm electric field.The magnetic hysteresis loops of the BLFNO film measured at room temperature confirmed the antiferromagnetic property of Bi0.975La0.025Fe0.975Ni0.025O3 film.%采用溶胶-凝胶法在Pt/Ti/SiO2/Si(111)衬底上制备了Bi0.975La0.025Fe0.975Ni0.025O3 (BLFNO)铁电薄膜.利用X射线衍射(XRD)、原子力显微镜(AFM)及其压电模式(PFM)对薄膜的晶体结构、表面形貌以及铁电畴结构进行了研究.研究发现,BLFNO为结晶良好的钙钛矿结构多晶薄膜,且薄膜表面颗粒生长均匀.PFM测试图显示铁电薄膜在自发极化下的铁电畴结构清晰,铁电电容器具有良好的铁电性能.应用铁电测试仪对Pt/BLFNO/Pt电容器进行测量,得到了饱和性良好的电滞回线.在828kV/cm的外加电场下,Pt/BLFNO/Pt电容器的剩余极化强度为74.3μC/cm2,表明La、Ni的共掺杂没有明显抑制铁电电容器的剩余极化强度,铁电电容器具有良好的铁电性能.漏电流研究结果表明,La、Ni元素的共掺杂有效降低了薄膜的漏电流密度,在277.8 kV/em外加电场下漏电流密度在10-4 A/cm2量级,明显小于纯BFO薄膜的漏电流密度.正半支漏电流曲线满足SCLC导电机制,对于负半支曲线,当电场强度大于22.2 kV/cm时,同样遵循SCLC导电机制;但是,当电场强度小于22.2 kV/cm时,曲线斜率约为4.8,表明参与导电贡献的电子数较多,归因于极浅陷阱俘获的电子在外加电场作用下参与了导电行为.室温下磁滞回线测试结果表明BLFNO薄膜具有反铁磁性质.
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