Experimental Technology and Management

该研究设计了一套综合性实验体系，系统探究SrRuO₃(SRO)、LaNiO₃(LNO)和LaSr_0.5Co_0.5O₃(LSCO)三种氧化物电极对Pb(Zr_0.4Ti0.₆)O₃(PZT)外延薄膜结构及物理性能的影响。通过集成铁电电容器制备技术、先进表征手段与实践教学需求，构建了涵盖薄膜沉积、界面工程、性能测试与机理分析的全流程实验框架。采用溶胶-凝胶法及磁控溅射技术制备了不同电极的PZT异质结，结合X射线衍射、原子力显微镜和拉曼光谱技术解析了薄膜的微观结构与界面特性，并通过铁电测试仪、介电谱仪和漏电流测试系统综合评估了它们的极化响应、介电行为及可靠性。实验通过“材料设计-工艺调控-性能优化”全链条实践教学体系，强化了学生在功能材料与器件领域的创新思维和工程实践能力。

[Objective] This study aims to systematically investigate the effects of three oxide electrodes—SrRuO₃(SRO), LaNiO₃(LNO), and LaSr_0.5Co_0.5O₃(LSCO)—on the structural and physical properties of Pb(Zr_0.4Ti_0.6)O₃(PZT) epitaxial thin films through a comprehensive experimental framework. By integrating advanced ferroelectric capacitor fabrication techniques, high-precision characterization methods, and hands-on training, the experiment focuses on elucidating the regulatory mechanisms of electrode materials on ferroelectric performance. It establishes a holistic workflow encompassing “material design, process optimization, and performance analysis” to deepen students' understanding of the relationship between interface engineering and device performance in ferroelectric heterojunctions. The experiment also provides scientific insights for optimizing the ferroelectric device performance. [Methods] This experiment combines magnetron sputtering and sol–gel techniques to fabricate PZT heterostructures with different electrodes on SrTiO₃(STO) substrates. A Ti₃Al buffer layer and bottom electrodes(SRO, LNO, LSCO) are sequentially deposited via magnetron sputtering. Subsequently, a 120-nm PZT epitaxial film is synthesized using sol–gel spin-coating followed by annealing. The top electrodes are patterned using a shadow mask. Structural characterization included X-ray diffraction(XRD) to analyze lattice orientation and crystallinity, atomic force microscopy(AFM) to evaluate surface morphology and roughness, and Raman spectroscopy to quantify residual stress. Ferroelectric properties(e.g., polarization hysteresis loops, ΔP–V response, pulse width dependence, and fatigue resistance) are measured using a ferroelectric tester, whereas dielectric constants and leakage current densities are assessed via an LCR meter and a Keithley source meter, respectively. Mechanisms underlying electrode-material-induced interface effects are systematically explored through lattice mismatch calculations, dislocation density analysis, and stress-performance correlation models. [Results](1) Structural Properties: XRD analysis revealed that the SRO electrode system exhibited superior epitaxial quality, with the narrowest full width at half maximum of 0.735° for the PZT(002) rocking curve and the lowest dislocation density(2.306×10¹⁰/cm²), indicating optimal lattice matching. Raman spectroscopy further confirmed that SRO electrodes minimized residual stress(2.41 GPa) because of the smallest lattice mismatch with PZT, compared with LNO(3.12 GPa) and LSCO(3.56 GPa), effectively suppressing the interface defect formation.(2) Ferroelectric Performance: Ferroelectric testing demonstrated that the SRO/PZT heterostructure achieved the highest remnant polarization(Pr= 108.50 μC/cm²), highlighting efficient polarization switching. In addition, its pulse-width-dependent stability(0.01–10 ms) and fatigue resistance(no degradation after 10⁹ switching cycles) underscored the enhanced domain dynamics owing to the reduced interfacial stress.(3) Dielectric and Leakage Characteristics: The SRO system displayed the highest dielectric constant(ε_r) with superior stability, while its leakage current density(J) was one and two orders of magnitude lower than those of LNO and LSCO systems, respectively, validating the optimized charge transport at the interface.(4) Surface Morphology: AFM characterization showed that the SRO-based PZT film exhibited the lowest root-mean-square roughness(RMS=1.18 nm), substantially lower than LNO(1.23 nm) and LSCO(2.75 nm), thereby emphasizing the critical role of lattice compatibility in achieving smooth surfaces. [Conclusions] This study systematically unravels the influence of electrode materials on the performance of PZT epitaxial films by integrating fabrication, characterization, and testing methodologies. The SRO electrode, owing to its exceptional lattice compatibility with PZT, considerably reduces the interfacial stress and dislocation density, thereby endowing the heterostructure with optimal comprehensive properties: highest remnant polarization, lowest leakage current, superior dielectric stability, and robust fatigue resistance. These findings not only provide theoretical guidance for electrode optimization in ferroelectric capacitors but also establish an integrated “fabrication-characterization-analysis” experimental framework that bridges theoretical knowledge and practical training. Through hands-on participation in thin-film deposition, instrument operation, and data analysis, students gain mastery over core characterization techniques and a profound understanding of the impact of interface engineering on device performance, effectively enhancing their research capabilities and innovative thinking in functional material science.