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摘要：多铁性材料是一种同时具备铁磁性、铁电性、铁弹性和铁旋性中的以上两种或两种以上性能的化合物。磁电复合材料是包含铁电性又具备铁磁性的多铁性复合材料，因为磁或电而引发两相之间界面相互作用，产生应力传递使它具备的磁电耦合效应，这种材料由于提供了一种由磁场控制极化或者由电场控制磁化的可能而备受关注。选用溶胶—凝胶法分别制备合成CoFe2O4、BaTiO3纳米级复合颗粒。然后，用高速球磨法制合成备CoFe2O4/BaTiO3复合陶瓷，同时研究了不同CoFe2O4含量配比对复合陶瓷显微结构以及磁电性能的影响。本文将CoFe2O4/BaTiO3复合粉体制备合成为陶瓷状块体材料，通过改变两相组份、烧结温度、保温时间三个工艺参数，合成了不同系列的复合多铁性材料样品。再通过对不同系列样品的铁电、介电、铁磁性能的研究，最终得到制备多铁陶瓷的最优工艺参数和条件。研究结果表明，CoFe2O4/BaTiO3两相粉体可获得最佳界面耦合，样品在两相配比为2:8、烧结温度为1200℃时获得最佳性能，最大电极化强度为0.98μC/cm2，最小漏电流为1.1×10-6Amps。23356
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毕业论文关键词：多铁性材料；磁电耦合效应；溶胶—凝胶；CoFe2O4/BaTiO3纳米复合材料
Synthesis and magneto-electric effect of CoFe2O4/BaTiO3 multiferroic composites
Abstract ：Multiferroic composites consisting of two or more materials with ferroelectric， ferromagnetic show a magnetoelectric (ME) coupling effect due to the magnetically or electrically induced mechanical deformation between two phases. These materials are attractive because they offer the possibility to control the polarization by a magnetic field or the magnetization by an electric field. The core-shell CoFe2O4 and BaTiO3 nanoparticles were prepared by sol-gel method. Futuremore，ferroelectric/ferrite composites of CoFe2O4/BaTiO3 ceramics were then synthesized by high-speed ball milling method. The difference of the ferroelectric and magnetic properties on the content and ratio of CoFe2O4 has been investigated systematically. A few series of CoFe2O4/BaTiO3 ceramics was prepared from powders by changing the preparation conditions，which include constituent，sintering temperature and sintering duration. The most appropriate preparation conditions，was obtained by the measurement of ferroelectric，dielectric and ferromagnetic properties. Finally, the CoFe2O4/BaTiO3 ceramics sintered at 1200℃ with 2:8 have the best coupling interface, sintering temperature and molar radio. Which has the highest polarization of 0.98µC/cm2 and the lowest leakage current of 1.1×10-6Apms.
Key words：Multiferroic；Magnetoelectric；Sol-Gel；CoFe2O4/BaTiO3 nanocomposites
目录
1绪论 1
1.1 尖晶石型钴铁氧体 1
1.2 钛酸钡 3
1.3 多铁性材料简介 6
1.4 磁电耦合效应 8
1.5 溶胶凝胶法 9
1.6 陶瓷型 CoFe2O4-BaTiO3磁电复合材料 10
1.7 选题的目的和研究内容 12
1.7.1 实验机理 12
1.7.2 研究内容 12
2实验部分 14
2.1 实验过程 14
2.1.1 CoFe2O4单体制备 14
2.1.2 BaTiO3单体制备 14
2.1.3 CoFe2O4/BaTiO3两相复合制备 14
2.1.4 压片及被银 15
2.2 实验原料及实验仪器和设备 16
2.2.1 实验原料 16
2.2.2 实验仪器及设备 16
2.2 仪器设备简介 17
2.2.1 行星式球磨机 17
2.2.2 XRD衍射仪 18
2.2.3 铁电测试原理 18