多铁性材料B位掺杂改性研究
本课题通过采用快速固相烧结法制备出BiFe1-xScxO3系列的陶瓷样品，并对其进行XRD结构分析、SEM形貌分析、介电性能分析和电滞回线分析。XRD结构分析发现较低浓度的Sc3+掺杂并不会改变其结构，但会使衍射峰左移因为Sc3+会使其晶胞增大。从SEM照片上看烧结温度为880℃时，样品的晶粒尺寸较大，致密度较好。介电性能分析表明介电常数会随着Sc掺杂浓度的提高而提高。通过铁电性能分析可以发现，Sc的掺杂浓度从0.03增加到0.05时，陶瓷的剩余极化率和矫顽电场都明显提高，分别从5.69μC/cm2增加到10.38μC/cm2，从1055Kv/cm增加到1269Kv/cm，BiFeO3的铁电性能提升。
关键词 铁酸铋陶瓷 Sc掺杂 XRD 介电性能 电滞回线
毕业论文设计说明书外文摘要
Title Research on the B-site doping of multiferroic materials
Abstract
At present,the research on multiferroic material is a rising area in the field of international functional material.The Magnetoelectric effect opens the new opportunities in magnetic recording, spintronics, etc. In this respect,BiFeO3 ,one of the most promising room temperature multiferroic material, exhibits a low spontaneous polarization and saturation magnetization values. The article gives an account of the research on the enhanced room temperature multiferroicity of BiFeO3 by using doping method .
In this dissertation,BiFe1-xScxO3 ceramic samples were prepared by the fast solid-phase sintering.The XRD analysis revealed that the low concentration doping of Sc did not change its structure, but diffraction peaks in the diffraction pattern shifted left slightly because doping Sc caused the cell increasing. SEM photographs confirmed 800℃ sintered grains were larger and performance were more excellent.Meanwhile,dielectric analysis showed that the dielectric constant were improved with the concentration of Sc doping getting higher. By analyzing ferroelectric properties,we reached a decision that when the concentration of Sc doping increased from 0.03 to 0.05, the residual polarization and coercive field of ceramics had increased significantly ,respectively from 5.69μC / cm2 to 10.38μC / cm2 and from 1055Kv / cm to 1269Kv / cm.Therefore,these results demonstrate
that the multiderrocity could be enhanced by doping Sc.
Keywords BiFeO3 ceramics,Sc-doped ，XRD，dielectric properties,ferroelectric hysteresis loop
目 次
1 引言 1
2 多铁性基本概念 2
2. 1铁磁性与铁电性 2
2. 2 多铁性简介 3
3 多铁性材料BiFeO3简介 4
3. 1 BiFeO3 结构 4
3. 2 BiFeO3陶瓷的制备工艺 5
3. 3 BiFeO3的研究现状 6
4 本课题的研究内容和意义 7
5 实验部分 8
5. 1实验原料 8
5. 2实验仪器 9
5. 3实验方法 9
5. 4 实验步骤 10
6 实验结果与分析 11
6. 1 XRD分析 13
6. 2 SEM形貌分析 15
6. 3介电性能测试 18