【作者】 刘牛；

【导师】 周东祥；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 本课题利用溶胶-凝胶法制备了纳米级的钛酸钡（BaTiO₃）粉体，利用共沉积法制备了钴铁氧体（CoFe₂O₄）粉体。对胶体悬浮液的配制进行了探索，采取乙醇加乙酰丙酮的体系，配制出了稳定的BaTiO₃、CoFe₂O₄、NiFe₂O₄胶体悬浮液。对胶体悬浮液的运动性质、电学性质和稳定性做了比较深入的研究，从微观上阐述了稳定的胶体悬浮液的形成机制。搭建了简易的电泳沉积平台，对电泳沉积用衬底电极材料Pt/Ti/SiO2/Si和ITO导电膜玻璃做了一定的比较研究。在ITO导电膜玻璃上电泳沉积出了BaTiO₃单层膜、CoFe₂O₄单层膜、NiFe₂O₄单层膜、BaTiO₃-CoFe₂O₄双层膜、BaTiO₃-NiFe₂O₄双层膜、BaTiO₃-CoFe₂O₄混合膜、BaTiO₃-NiFe₂O₄混合膜。对BaTiO₃单层膜而言，沉积电压30V，沉积时间10min可以得到比较合格的BaTiO₃单层膜。CoFe₂O₄单层膜的一般沉积电压为30V，沉积时间为3min。NiFe₂O₄单层膜的沉积电压是30V，沉积时间取2min。以上三种单层膜的退火工艺都是以250℃/h的升温速率，550℃下保温20min。制得合格的BaTiO₃单层膜后，在其上面继续电泳沉积CoFe₂O₄或者NiFe₂O₄，这样就得到了BaTiO₃-CoFe₂O₄双层膜或者BaTiO₃-NiFe₂O₄双层膜。用BaTiO₃粉体和CoFe₂O₄粉体配制成的混合悬浮液，可以电泳沉积得到BaTiO₃-CoFe₂O₄混合膜。BaTiO₃粉体和NiFe₂O₄粉体配制成的混合悬浮液，可电泳沉积BaTiO₃-NiFe₂O₄混合膜。对薄膜的表面形貌和电磁性能做了分析。BaTiO₃单层膜的铁电性能较好，CoFe₂O₄单层膜和NiFe₂O₄单层膜的铁磁性能较好。由于双层膜和混合膜表面都一定程度地存在漏电流，所以其铁电性能不理想。相比较而言，BaTiO₃-CoFe₂O₄双层膜和BaTiO₃-CoFe₂O₄混合膜的矫顽力和剩磁较大，但是漏电流过大，铁电性能不理想；BaTiO₃-NiFe₂O₄双层膜和BaTiO₃-NiFe₂O₄混合膜的矫顽力和剩磁很小，属于明显的软磁材料，其铁电性能比BaTiO₃-CoFe₂O₄双层膜和BaTiO₃-CoFe₂O₄混合膜的好一些。更多还原

【Abstract】 Prepare nano-barium titanate （BaTiO₃） powders by a sol-gel method, and prepare ironcobalt （CoFe₂O₄） powders by a co-deposition method.Find out a suitable way to prepare colloidal suspensions, get a stable BaTiO₃suspension, CoFe₂O₄ suspension and NiFe₂O₄ suspension by the system of acetylacetoneand ethanol. Study the movement, electrical properties and stability of the suspensions,expla in the formation mecha nism of a stable colloidal suspension.Build a simple platform for the electrophoretic deposition, do some studies about thesubstrates such as Pt/Ti/SiO 2/Si and ITO conductive film glass. And then get a BaTiO₃single-la yer film, a CoFe₂O₄ single-la yer film, a NiFe₂O₄ single-la yer film, a BaTiO₃-CoFe₂O₄ double-la yer film, a BaTiO₃-NiFe₂O₄ double-la yer film, a BaTiO₃-CoFe₂O₄ mixedfilm, a BaTiO₃-NiFe₂O₄ mixed film by the electrophoretic deposition method on ITOconductive film glasses. For the BaTiO₃ single-la yer film, the most appropriate depositionvoltage is 30V, deposition time is 10min. For the CoFe₂O₄ single-la yer film, the commondeposition voltage is 30V, deposition time is 3min. For the NiFe₂O₄ single-la yer film, thecommon deposition voltage is 30V, deposition time is 2min. And their annealing conditionis sintered at 550℃for 20min.Analyse the surface morphology and electroma gnetic properties of the films. TheBaTiO₃ single-la yer film’s ferroelectric properties is not bad, so as the ferroma gneticproperties of the CoFe₂O₄ single-la yer film or NiFe₂O₄ single-la yer film. The hysteresis loopis not so well because of the leakage current on the surface of double-la yer and mixed films.Comparatively speaking, the coercivity（Hc） and resid ual ma gnetization（Mr） of BaTiO₃-CoFe₂O₄ double-la yer film and BaTiO₃-CoFe₂O₄ mixed film are higher, but theirferroelectric properties are bad for the large leakage current; the coercivity（Hc） and resid ualma gnetization（Mr） of BaTiO₃-NiFe₂O₄ double-la yer film and BaTiO₃-NiFe 2O4 mixed filmare very sma ll, but their ferroelectric properties are better.更多还原