Microscopic origin of the simultaneous ferroelectric and magnetic phase transition of RMn_2O_5

RMn_2O_5同时铁电和磁相变的微观起源

• 批准号: 16340096
• 负责人: NODA Yukio
• 金额: $ 10.11万
• 依托单位: Tohoku University
• 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
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16340096/
• 关键词: multiferroic; magnetic order; ferroelectric; neutron magnetic scattering; synchrotron x-ray; electro-magnetic effect; RMn_2O_5; RMn2O5; RMm205; 誘電率測定

We performed the following investigations and published the results.(1)Magnetic propagation vectors q_M of RMn_2O_5(R=Er, Tb, Ho, Tm).(2)Developing the method to measure q_M, dielectric constant E and electric polarization Ps simultaneously.(3)Reinvestigation of the dielectric constant of RMn_2O_5,and found the generalized phase diagram.(4)Synchrotron x-ray experiments to find new Bragg reflections corresponding to the ferroelectric.(5)Polarized neutron scattering of HoMn_2O_5 to measure the spin-chirality.(6)Neutron scattering experiments of HoMn_2O_5 and ErMn_2O_5 at low temperature under external magnetic field.We confirmed that the successive magnetic and ferroelectric phase transitions in RMn_2O_5 occur at the same temperatures. Further, we show that the first ferroelectric phase transition has the same character regardless of the rare earth element R of RMn_2O_5. On the other hand, the giant electro-magnetic effect at the lowest temperature region strongly depends on R. We have s … More hown that the magnetic ordering under the external magnetic field induces such giant electro-magnetic effect. That is, magnetic ordering induces ferroelectric polarization. This result was awarded by Journal of the Physical Society of Japan. After the simultaneous measurements of q_M,ε and Ps, we have the feeling that the scenario we proposed must be changed slightly since very weak ferroelectric component is seen between the one-dimensionally moderated magnetic phase and magnetic commensurate phase. Measure part of the electric polarization shows up below the magnetic commensurate phase. Such phenomena might be related to the existence of the so-called discommensuration. We also performed synchrotron x-ray diffraction to know the true structure at the ferroelectric phase. The unit cell size is double along c-direction and the space group is Pb2_1m. Very weak new Brag reflections were measured at (001/2) and (000) positions, whose intensities are 8-order magnitude weaker than the fundamental Bragg reflections. Less

我们进行了以下调查并公布了结果。（1）RMn_2O_5（R=Er，Tb，Ho，Tm）的磁传播矢量q_M。（2）建立了同时测量介电常数、介电常数和极化率的方法。（3）重新研究了RMn_2O_5的介电常数，建立了广义相图。（4）同步辐射X射线实验，寻找铁电体的新布拉格反射。（5）HoMn_2O_5的极化中子散射测量。（6）HoMn_2O_5和ErMn_2O_5在低温外磁场作用下的中子散射实验，证实了RMn_2O_5在相同温度下发生连续的磁性和铁电性相变。此外，我们还发现，无论RMn_2O_5中的稀土元素R是多少，其第一铁电相变都具有相同的特征。另一方面，在最低温度区的巨电磁效应强烈地依赖于R。我们有 ...更多信息 表明在外加磁场作用下的磁有序引起了这种巨电磁效应。也就是说，磁有序诱导铁电极化。这一结果由日本物理学会杂志授予。在同时测量了qM、ε和Ps之后，我们感觉到我们提出的方案必须稍微改变，因为在一维慢化磁相与磁公度相之间观察到非常弱的铁电组分。测量部分的电极化显示在磁公度相以下。这种现象可能与所谓的异化现象的存在有关。我们还进行了同步辐射X射线衍射，以了解铁电相的真实结构。晶胞尺寸沿沿着c方向为2倍，空间群为Pb 2_1m。在（001/2）和（000）位置测量到非常弱的新布拉格反射，其强度比基本布拉格反射弱8个数量级。少

项目成果

Reinvestigation of Simultaneous Magnetic and Ferroelectric Phase Transitions in YMn2O5

• DOI: 10.1143/jpsj.73.1593
• 发表时间: 2004-06
• 期刊: Journal of the Physical Society of Japan
• 影响因子: 1.7
• 作者: Satoru Kobayashi;T. Osawa;H. Kimura;Y. Noda;I. Kagomiya;K. Kohn

Simultaneous Measurements of Magnetic Neutron Diffraction, Electrical Polarization and Permittivity of Multiferroic ErMn2O5

同时测量多铁性 ErMn2O5 的磁中子衍射、电极化和介电常数

• DOI: 10.1143/jpsj.76.074710
• 发表时间: 2007
• 期刊: Journal of the Physical Society of Japan
• 影响因子: 1.7
• 作者: M. Fukunaga;K. Nishihata;H. Kimura;Y. Noda;K. Kohn
• 通讯作者: K. Kohn

Relation between ferroelectric and antiferromagnetic order in RMn2O5

• DOI: 10.1016/j.physb.2006.05.179
• 发表时间: 2006-11
• 期刊: Physica B-condensed Matter
• 影响因子: 2.8
• 作者: Y. Noda;H. Kimura;Y. Kamada;T. Osawa;Yosikazu Fukuda;Y. Ishikawa;Satoru Kobayashi;Y. Wakabayashi;H. Sawa;N. Ikeda;K. Kohn

Field-induced dielectric and magnetic phase transition in multiferroic compounds of RMn_2O_5(R=Er, Ho)

RMn_2O_5(R=Er, Ho)多铁性化合物场致介电相变和磁相变

• 发表时间: 2007
• 期刊: J. Korean Phys. Soc. (印刷中)
• 作者: K.Hattori;Y.Hirayama;K.Miyake;K.Hattori;K.Hoshihara;H.Kamei;K.Hattori;K.Hoshihara;M.Fukunaga;H.Maebashi;H.Kimura
• 通讯作者: H.Kimura

Spiral spin structure in commensurate magnetic phase of multiferroic RMn_2O_5

多铁性RMn_2O_5相应磁相中的螺旋自旋结构

• 发表时间: 2007
• 期刊: J. Phys. Soc. Jpn. 76(No7)(印刷中)
• 作者: K.Hattori;Y.Hirayama;K.Miyake;K.Hattori;K.Hoshihara;H.Kamei;K.Hattori;K.Hoshihara;M.Fukunaga;H.Maebashi;H.Kimura;Y.Noda;K.Hattori;M.Fukunaga;H.Kimura;Y.Fuseya;H.Kimura
• 通讯作者: H.Kimura