Preparation of Transparent Oxides With Ferromagnetic and Ferroelectric Properties at room temperature by Doping Mn and La

掺杂Mn、La制备室温铁磁、铁电透明氧化物

基本信息

批准号：
14550295
负责人：
GOMI Manabu
金额：
$ 2.3万
依托单位：
Nagoya Institute of Technology (2003)Japan Advanced Institute of Science and Technology (2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

In this research, we have investigated the mechanism of ferromagnetic behavior exhibiting high Curie temperatures observed for perovskite-type dielectric oxides ABO_3(A=Sr, Ba, Ca, Pb, B=Ti, Zr) doped with La-Mn. In addition, we discussed the possibility of electric field-controlled magnetism through the investigation of relationship between the ferromagnetic and dielectric properties. The obtained results are as follows;1. La-Mn doped ATiO_3 (A=Sr, Ba, Ca) ceramics are ferromagnetic at room temperature, exhibiting magnetizations proportional to the Mn amount. The magnitude of observed magnetization depends on the final sintering temperature, reduced rapidly above 1200℃ at which the sintering density becomes higher.2. The high-resolution TEM observation and EDX composition analysis showed that there is a Mn-rich crystalline region around the grain boundaries for some La-Mn : BaTiO_3 ceramics. In addition, small peaks indicative of the ferromagnetic phase (La, Ba) MnO_3 were detected for these ceramics with the doped amount of La and Mn increasing.These result indicated that the ferromagnetism observed at room temperature is possibly ascribed to precipitation of a small amount of ferromagnetic manganite into the dielectric matrix.3. The 1 mol. % La-Mn doped BaTio_3 ceramics exhibiting simultaneously large magnetization and ferroelectricity at room temperature have been successfully prepared for the first time.It was found that the spontaneous magnetization of 1 mol. % La-Mn doped BaTio_3 ceramics exhibits the reduction as large as 45% for the applied electric field of 1.3 KV/mm. This reduction of magnetization by the electric field is of achieved for the first time and open the door to the control of magnetic moment using electric field.

在本研究中，我们研究了掺杂 La-Mn 的钙钛矿型电介质氧化物 ABO_3(A=Sr、Ba、Ca、Pb、B=Ti、Zr) 表现出高居里温度的铁磁行为的机制。通过研究La-Mn掺杂的铁磁性能和介电性能之间的关系，讨论了电场控制磁性的可能性； 1． ATiO_3（A=Sr、Ba、Ca）陶瓷在室温下具有铁磁性，磁化强度与Mn量成正比。观察到的磁化强度取决于最终烧结温度，在1200℃以上烧结密度变高时迅速降低。 2. 高分辨率TEM观察和EDX成分分析表明，某些La-Mn晶界周围存在富Mn结晶区域：此外，随着La和Mn掺杂量的增加，这些陶瓷中检测到了指示铁磁相(La，Ba)MnO_3的小峰。这些结果表明，在室温下观察到的铁磁性可能归因于铁磁相(La，Ba)MnO_3的沉淀。少量的铁磁锰酸盐进入介电基体中。 3．首次成功制备出在室温下同时表现出大磁化强度和铁电性的材料。研究发现，1 mol% La-Mn 掺杂的 BaTio_3 陶瓷的自发磁化强度在外加电场下降低了 45%。 1.3 KV/mm 首次实现了通过电场降低磁化强度，并为利用电场控制磁矩打开了大门。