bifeo3薄膜的制备及其铁电性能分析word格式论文.docx

AbstractOccupying an important position in the modern society, information storage devices put forward a higher request for material. BiFeO3 is a promising ferroelectric material for high-density ferroelectric random access memory (FeRAM) due to its high Curie temperature of TC ≈ 1104 K, giant remnant polarization of Pr ≈ 100 μC/cm2, and environmental friendliness. Attributed to epitaxial strain, which leads to the structural distortion and small changes in lattice parameters, the remnant polarization in BiFeO3 thin film was found to be one order higher than that of bulk BiFeO3. Furthermore, according to the demand of electronic device miniaturization and integration, BiFeO3 thin film has gained remarkable attention. Nevertheless, BiFeO3 thin film suffers from high leakage current, which leads to the discrepancy between its current performance status and practical application requirements. Fe ions valence fluctuation and oxygen vacancies are mostly considered to be the crucial factors.In this dissertation, we focus on sample preparation at first. Then based on the optimized fabrication technology, we get the sample of enhanced ferroelectric properties through Cr3+ doping modification. This dissertation mainly includes the following conclusions:A sol-gel method has been developed to synthesize the BiFeO3 thin films. The effects of preparation process, including sol preparation, spinning and heat treatment, on the structure, morphology and performance of the BiFeO3 thin films have been studied. The BiFeO3 thin films were prepared under the condition of sol concentrationof 0.20 mol/L and by the step-by-step annealing meathod at 600 ℃. The BiFeO3 thinfilms show pure phase and R3c space group. And the sample are dense and own a columnar structure.The effects of Cr doping on the structure, morphology and performance of the BiFeO3 thin films have been studied. Chromium (Cr) substitution induced the crystalstructure transformation fromR3c space group toR3m space group. D