Creation of room-temperature-multiferroic oxides and electric-field-controlled magnetization

室温多铁氧化物的制备和电场控制磁化

基本信息

批准号：
16360151
负责人：
GOMI Manabu
金额：
$ 7.74万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

New materials exhibiting a large magnetoelectric effect due to coexistence of ferromagnetism and ferroelectricity at room temperature have been investigated. The following research results are obtained ;1.Electric-field-induced magnetization reduction and the mechanism in oxides exhibiting simultaneously ferromagnetism and ferroelectrics.(1)Coexistence of ferromagnetism and ferroelectricity observed in La, Mn : BaTiO_3 and BaTiO_3-LaMnO_3 composites are due to a small amount of ferromagnetic (La, Ba)MnO_3 phase precipitated into the grain boundaries or the inside of the ferroelectric grains.(2)The composites BaTiO_3-LaMnO_3 are materials simultaneously exhibiting ferroelectricity and a relatively ferromagnetic magnetization at room temperature. The density and dielectric properties of the composites markedly improved with the grain size of LaMnO_3 decreasing. When an electric field of 750 V/mm was applied to the composites, magnetization reduction as large as 25 % was observed for the … More first time.(3)An electric-field-induced magnetization reduction similar to that in the composites was observed for BaTiO_3/BaTiO_3-LaMnO_3 composite / BaTiO_3 structures where a composite was sandwiched between ferroelectric insulator BaTiO_3 layers. This suggests that the observed magnetization reduction is probably not due to thermal effect but intrinsic field-induced effect. Change of hole concentration in (La, Ba)MnO_3 induced by the dielectric polarization may be responsible for the magnetization reduction.(4)An electric-field-induced magnetization reduction of 2.2 % for the applied voltage of 4V was observed in a BaTiO_3/(La, Ba)MnO_3/BaTiO_3 layer structure. This is direct evidence showing the magnetization change to originate from the induced polarization.2.Search for new multiferroic materials(1)Pb(Zr, Ti)O_3-LaMnO_3 composites are new multiferroics with higher ferroelectric Curie temperature and larger polarization than BaTiO_3 system. It has been found for the first time that they exhibits a magnetization reduction as large as 30 % for a low applied electric field of 0.4 kV/mm at room temperature. Less

由于已经研究了由于室温下的铁磁和铁电的共存而表现出巨大磁电效应的新材料。 The following research results are obtained ;1.Electric-field-induced magnetization reduction and the mechanism in oxides exhibiting simply ferromagnetism and ferroelectricity observed in La, Mn : BaTiO_3 and BaTiO_3-LaMnO_3 companies are due to a small amount of ferromagnetic (La, Ba)MnO_3 phase precious into the grain boundaries or the inside of the ferroelectric谷物。（2）BATIO_3-LAMNO_3的组成是仅在室温下进行铁电性和相对铁电磁磁化的材料。随着Lamno_3的晶粒尺寸的减小，组合物的密度和顽固特性显着提高。当将750 v/mm的电场应用于组合物上时，在…更高的第一次观察到的磁化减少至25％。（3）电场诱导的磁化减少与Batio_3/batio_3/batio_3-lamno_3-lamno_3 composite/batio_3结构相似的组合物中相似的磁化磁化强度，其中一个组合的固定剂是隔离式的。这表明观察到的磁化减少可能不是由于热效应，而是固有的磁场诱导的效应。词典极化引起的（LA，BA）MNO_3中的孔浓度的变化可能是降低磁化的原因。（4）在BATIO_3/（LA，BA）MNO_3/BATIO_3/BATIO_3层结构中观察到了4V的电场诱导的磁化降低2.2％。这是表明磁化变化源于诱导极化的直接证据。2。对新的多用量材料（1）PB（ZR，TI）O_3-LAMNO_3复合材料进行搜索是具有更高铁电居里温度和比BATIO_3系统更大的偏振的新的多表情。在室温下，低至0.4 kV/mm的低施加电场，他们首次发现它们的磁化降低至30％。较少的